Merge GH #665 Add IncludeOS target, make filesystem/threads optional

83 files changed, 342 insertions, 89 deletions

diff --git a/configure.py b/configure.py
index f314a9d57..47a5b473c 100755
--- a/configure.py
+++ b/configure.py
@@ -1784,6 +1784,16 @@ def generate_amalgamation(build_config, options):
 
         if tgt not in botan_amalg_files:
             botan_amalg_files[tgt] = open_amalg_file(tgt)
+
+            if tgt != '':
+                for isa in mod.need_isa:
+                    if isa == 'aesni':
+                        isa = "aes,ssse3,pclmul"
+                    elif isa == 'rdrand':
+                        isa = 'rdrnd'
+
+                    botan_amalg_files[tgt].write('#if defined(__GNUG__)\n#pragma GCC target ("%s")\n#endif\n' % (isa))
+
         if tgt not in headers_written:
             headers_written[tgt] = headers_written_in_h_files.copy()
 
diff --git a/src/build-data/buildh.in b/src/build-data/buildh.in
index e943973a0..c84698804 100644
--- a/src/build-data/buildh.in
+++ b/src/build-data/buildh.in
@@ -199,8 +199,15 @@ Each read generates 32 bits of output
 
 %{target_compiler_defines}
 
+
+#if defined(__GNUG__) || defined(__clang__)
+  #define BOTAN_FUNC_ISA(isa) __attribute__ ((target(isa)))
+#else
+  #define BOTAN_FUNC_ISA(isa)
+#endif
+
 /*
-* Compile-time deprecatation warnings
+* Compile-time deprecation warnings
 */
 #if !defined(BOTAN_NO_DEPRECATED_WARNINGS)
 
diff --git a/src/build-data/os/aix.txt b/src/build-data/os/aix.txt
index 369b720c4..de417ce90 100644
--- a/src/build-data/os/aix.txt
+++ b/src/build-data/os/aix.txt
@@ -2,4 +2,6 @@ os_type unix
 
 <target_features>
 gettimeofday
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/android.txt b/src/build-data/os/android.txt
index 43e5fdc44..64a639909 100644
--- a/src/build-data/os/android.txt
+++ b/src/build-data/os/android.txt
@@ -11,4 +11,6 @@ posix_mlock
 gmtime_r
 dlopen
 readdir
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/cygwin.txt b/src/build-data/os/cygwin.txt
index ee934f787..956f5b28d 100644
--- a/src/build-data/os/cygwin.txt
+++ b/src/build-data/os/cygwin.txt
@@ -13,4 +13,6 @@ doc_dir docs
 <target_features>
 gettimeofday
 timegm
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/darwin.txt b/src/build-data/os/darwin.txt
index f95e8f5e8..662101b1c 100644
--- a/src/build-data/os/darwin.txt
+++ b/src/build-data/os/darwin.txt
@@ -18,6 +18,8 @@ memset_s
 readdir
 timegm
 sockets
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/build-data/os/dragonfly.txt b/src/build-data/os/dragonfly.txt
index f9137d3c1..1ff2804b0 100644
--- a/src/build-data/os/dragonfly.txt
+++ b/src/build-data/os/dragonfly.txt
@@ -5,4 +5,6 @@ clock_gettime
 gettimeofday
 posix_mlock
 sockets
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/freebsd.txt b/src/build-data/os/freebsd.txt
index 9d6ed3614..326e6661a 100644
--- a/src/build-data/os/freebsd.txt
+++ b/src/build-data/os/freebsd.txt
@@ -13,4 +13,6 @@ dlopen
 readdir
 timegm
 sockets
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/haiku.txt b/src/build-data/os/haiku.txt
index 8e35e76eb..9ad3f29f7 100644
--- a/src/build-data/os/haiku.txt
+++ b/src/build-data/os/haiku.txt
@@ -8,6 +8,8 @@ doc_dir system/documentation
 <target_features>
 gettimeofday
 gmtime_r
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/build-data/os/hpux.txt b/src/build-data/os/hpux.txt
index 22d51ef0a..3f6f0d940 100644
--- a/src/build-data/os/hpux.txt
+++ b/src/build-data/os/hpux.txt
@@ -2,6 +2,8 @@ os_type unix
 
 <target_features>
 gettimeofday
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/build-data/os/hurd.txt b/src/build-data/os/hurd.txt
index e3906f63a..35a65315d 100644
--- a/src/build-data/os/hurd.txt
+++ b/src/build-data/os/hurd.txt
@@ -2,6 +2,8 @@ os_type unix
 
 <target_features>
 posix_mlock
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/build-data/os/includeos.txt b/src/build-data/os/includeos.txt
new file mode 100644
index 000000000..423575b4a
--- /dev/null
+++ b/src/build-data/os/includeos.txt
@@ -0,0 +1,7 @@
+os_type unikernel
+
+building_shared_supported no
+
+<target_features>
+includeos_rng
+</target_features>
diff --git a/src/build-data/os/irix.txt b/src/build-data/os/irix.txt
index 369b720c4..de417ce90 100644
--- a/src/build-data/os/irix.txt
+++ b/src/build-data/os/irix.txt
@@ -2,4 +2,6 @@ os_type unix
 
 <target_features>
 gettimeofday
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/linux.txt b/src/build-data/os/linux.txt
index 42f101c3d..cb6c75df9 100644
--- a/src/build-data/os/linux.txt
+++ b/src/build-data/os/linux.txt
@@ -13,6 +13,8 @@ dlopen
 readdir
 timegm
 sockets
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/build-data/os/mingw.txt b/src/build-data/os/mingw.txt
index 5c72099e0..45fad382d 100644
--- a/src/build-data/os/mingw.txt
+++ b/src/build-data/os/mingw.txt
@@ -25,4 +25,6 @@ loadlibrary
 mkgmtime
 win32_virtual_lock
 win32_get_systemtime
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/nacl.txt b/src/build-data/os/nacl.txt
index 3df798ed8..e2e2f34be 100644
--- a/src/build-data/os/nacl.txt
+++ b/src/build-data/os/nacl.txt
@@ -1,4 +1,5 @@
 
 <target_features>
 gettimeofday
+threads
 </target_features>
diff --git a/src/build-data/os/netbsd.txt b/src/build-data/os/netbsd.txt
index 510a7accd..baf4b1a9c 100644
--- a/src/build-data/os/netbsd.txt
+++ b/src/build-data/os/netbsd.txt
@@ -8,4 +8,6 @@ gmtime_r
 dlopen
 readdir
 timegm
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/openbsd.txt b/src/build-data/os/openbsd.txt
index dfe3d2edf..0e18eb8e1 100644
--- a/src/build-data/os/openbsd.txt
+++ b/src/build-data/os/openbsd.txt
@@ -9,4 +9,6 @@ dlopen
 readdir
 timegm
 sockets
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/qnx.txt b/src/build-data/os/qnx.txt
index 4c0965764..a2061594f 100644
--- a/src/build-data/os/qnx.txt
+++ b/src/build-data/os/qnx.txt
@@ -6,4 +6,6 @@ gettimeofday
 posix_mlock
 gmtime_r
 dlopen
+threads
+filesystem
 </target_features>
diff --git a/src/build-data/os/solaris.txt b/src/build-data/os/solaris.txt
index 0ed785036..1e740aea7 100644
--- a/src/build-data/os/solaris.txt
+++ b/src/build-data/os/solaris.txt
@@ -6,6 +6,8 @@ install_cmd_exec '/usr/ucb/install -m 755'
 <target_features>
 posix_mlock
 gettimeofday
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/build-data/os/windows.txt b/src/build-data/os/windows.txt
index 32236e00b..679dfe651 100644
--- a/src/build-data/os/windows.txt
+++ b/src/build-data/os/windows.txt
@@ -21,6 +21,8 @@ query_perf_counter
 virtual_lock
 rtlsecurezeromemory
 stl_filesystem_msvc
+threads
+filesystem
 </target_features>
 
 <aliases>
diff --git a/src/lib/asn1/oid_lookup/oids.cpp b/src/lib/asn1/oid_lookup/oids.cpp
index cdb863494..8ee10b75a 100644
--- a/src/lib/asn1/oid_lookup/oids.cpp
+++ b/src/lib/asn1/oid_lookup/oids.cpp
@@ -7,7 +7,7 @@
 
 #include <botan/oids.h>
 #include <botan/parsing.h>
-#include <mutex>
+#include <botan/mutex.h>
 #include <sstream>
 
 namespace Botan {
@@ -27,7 +27,7 @@ class OID_Map
 
       void add_str2oid(const OID& oid, const std::string& str)
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          auto i = m_str2oid.find(str);
          if(i == m_str2oid.end())
             m_str2oid.insert(std::make_pair(str, oid));
@@ -35,7 +35,7 @@ class OID_Map
 
       void add_oid2str(const OID& oid, const std::string& str)
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          auto i = m_oid2str.find(oid);
          if(i == m_oid2str.end())
             m_oid2str.insert(std::make_pair(oid, str));
@@ -43,7 +43,7 @@ class OID_Map
 
       std::string lookup(const OID& oid)
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
 
          auto i = m_oid2str.find(oid);
          if(i != m_oid2str.end())
@@ -54,7 +54,7 @@ class OID_Map
 
       OID lookup(const std::string& str)
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
 
          auto i = m_str2oid.find(str);
          if(i != m_str2oid.end())
@@ -72,7 +72,7 @@ class OID_Map
 
       bool have_oid(const std::string& str)
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          return m_str2oid.find(str) != m_str2oid.end();
          }
 
@@ -92,14 +92,14 @@ class OID_Map
          read_cfg(cfg, "builtin");
          }
 
-      std::mutex m_mutex;
+      mutex_type m_mutex;
       std::map<std::string, OID> m_str2oid;
       std::map<OID, std::string> m_oid2str;
    };
 
 void OID_Map::read_cfg(std::istream& cfg, const std::string& source)
    {
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    size_t line = 0;
 
diff --git a/src/lib/base/algo_registry.h b/src/lib/base/algo_registry.h
index f7e66b3e2..bca3715b6 100644
--- a/src/lib/base/algo_registry.h
+++ b/src/lib/base/algo_registry.h
@@ -13,7 +13,7 @@
 #include <botan/exceptn.h>
 #include <botan/scan_name.h>
 #include <functional>
-#include <mutex>
+#include <botan/mutex.h>
 #include <vector>
 #include <map>
 #include <string>
@@ -77,14 +77,14 @@ class Algo_Registry
 
       void add(const std::string& name, const std::string& provider, maker_fn fn, byte pref)
          {
-         std::lock_guard<mutex> lock(m_mutex);
+         lock_guard_type<af_mutex_type> lock(m_mutex);
          if(!m_algo_info[name].add_provider(provider, fn, pref))
             throw Exception("Duplicated registration of " + name + "/" + provider);
          }
 
       std::vector<std::string> providers_of(const Spec& spec)
          {
-         std::lock_guard<mutex> lock(m_mutex);
+         lock_guard_type<af_mutex_type> lock(m_mutex);
          auto i = m_algo_info.find(spec.algo_name());
          if(i != m_algo_info.end())
             return i->second.providers();
@@ -93,7 +93,7 @@ class Algo_Registry
 
       void set_provider_preference(const Spec& spec, const std::string& provider, byte pref)
          {
-         std::lock_guard<mutex> lock(m_mutex);
+         lock_guard_type<af_mutex_type> lock(m_mutex);
          auto i = m_algo_info.find(spec.algo_name());
          if(i != m_algo_info.end())
             i->second.set_pref(provider, pref);
@@ -137,16 +137,16 @@ class Algo_Registry
    private:
 
 #if defined(BOTAN_WORKAROUND_GH_321)
-      using mutex = WinCS_Mutex;
+      using af_mutex_type = WinCS_Mutex;
 #else
-      using mutex = std::mutex;
+      using af_mutex_type = mutex_type;
 #endif
 
       Algo_Registry()  { }
 
       std::vector<maker_fn> get_makers(const Spec& spec, const std::string& provider)
          {
-         std::lock_guard<mutex> lock(m_mutex);
+         lock_guard_type<af_mutex_type> lock(m_mutex);
          return m_algo_info[spec.algo_name()].get_makers(provider);
          }
 
@@ -208,7 +208,7 @@ class Algo_Registry
             std::unordered_map<std::string, maker_fn> m_maker_fns;
          };
 
-      mutex m_mutex;
+      af_mutex_type m_mutex;
       std::unordered_map<std::string, Algo_Info> m_algo_info;
    };
 
diff --git a/src/lib/base/scan_name.cpp b/src/lib/base/scan_name.cpp
index 08f5e8702..76d9b1a17 100644
--- a/src/lib/base/scan_name.cpp
+++ b/src/lib/base/scan_name.cpp
@@ -172,7 +172,7 @@ size_t SCAN_Name::arg_as_integer(size_t i, size_t def_value) const
    return to_u32bit(m_args[i]);
    }
 
-std::mutex SCAN_Name::g_alias_map_mutex;
+mutex_type SCAN_Name::g_alias_map_mutex;
 std::map<std::string, std::string> SCAN_Name::g_alias_map = {
    { "3DES",            "TripleDES" },
    { "ARC4",            "RC4" },
@@ -197,7 +197,7 @@ std::map<std::string, std::string> SCAN_Name::g_alias_map = {
 
 void SCAN_Name::add_alias(const std::string& alias, const std::string& basename)
    {
-   std::lock_guard<std::mutex> lock(g_alias_map_mutex);
+   lock_guard_type<mutex_type> lock(g_alias_map_mutex);
 
    if(g_alias_map.find(alias) == g_alias_map.end())
       g_alias_map[alias] = basename;
@@ -205,7 +205,7 @@ void SCAN_Name::add_alias(const std::string& alias, const std::string& basename)
 
 std::string SCAN_Name::deref_alias(const std::string& alias)
    {
-   std::lock_guard<std::mutex> lock(g_alias_map_mutex);
+   lock_guard_type<mutex_type> lock(g_alias_map_mutex);
 
    std::string name = alias;
 
diff --git a/src/lib/base/scan_name.h b/src/lib/base/scan_name.h
index c19bbf50f..75f7d1089 100644
--- a/src/lib/base/scan_name.h
+++ b/src/lib/base/scan_name.h
@@ -11,7 +11,7 @@
 #include <botan/types.h>
 #include <string>
 #include <vector>
-#include <mutex>
+#include <botan/mutex.h>
 #include <map>
 
 namespace Botan {
@@ -117,7 +117,7 @@ class BOTAN_DLL SCAN_Name
       */
       static std::string deref_alias(const std::string& alias);
    private:
-      static std::mutex g_alias_map_mutex;
+      static mutex_type g_alias_map_mutex;
       static std::map<std::string, std::string> g_alias_map;
 
       std::string m_orig_algo_spec;
diff --git a/src/lib/block/aes_ni/aes_ni.cpp b/src/lib/block/aes_ni/aes_ni.cpp
index 3377f9d61..7518a6cf2 100644
--- a/src/lib/block/aes_ni/aes_ni.cpp
+++ b/src/lib/block/aes_ni/aes_ni.cpp
@@ -13,6 +13,7 @@ namespace Botan {
 
 namespace {
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_128_key_expansion(__m128i key, __m128i key_with_rcon)
    {
    key_with_rcon = _mm_shuffle_epi32(key_with_rcon, _MM_SHUFFLE(3,3,3,3));
@@ -22,6 +23,7 @@ __m128i aes_128_key_expansion(__m128i key, __m128i key_with_rcon)
    return _mm_xor_si128(key, key_with_rcon);
    }
 
+BOTAN_FUNC_ISA("ssse3")
 void aes_192_key_expansion(__m128i* K1, __m128i* K2, __m128i key2_with_rcon,
                            u32bit out[], bool last)
    {
@@ -51,6 +53,7 @@ void aes_192_key_expansion(__m128i* K1, __m128i* K2, __m128i key2_with_rcon,
 /*
 * The second half of the AES-256 key expansion (other half same as AES-128)
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 __m128i aes_256_key_expansion(__m128i key, __m128i key2)
    {
    __m128i key_with_rcon = _mm_aeskeygenassist_si128(key2, 0x00);
@@ -103,6 +106,7 @@ __m128i aes_256_key_expansion(__m128i key, __m128i key2)
 /*
 * AES-128 Encryption
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_128::aesni_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -179,6 +183,7 @@ void AES_128::aesni_encrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-128 Decryption
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_128::aesni_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -255,6 +260,7 @@ void AES_128::aesni_decrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-128 Key Schedule
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_128::aesni_key_schedule(const byte key[], size_t)
    {
    m_EK.resize(44);
@@ -307,6 +313,7 @@ void AES_128::aesni_key_schedule(const byte key[], size_t)
 /*
 * AES-192 Encryption
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_192::aesni_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -389,6 +396,7 @@ void AES_192::aesni_encrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-192 Decryption
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_192::aesni_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -471,6 +479,7 @@ void AES_192::aesni_decrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-192 Key Schedule
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_192::aesni_key_schedule(const byte key[], size_t)
    {
    m_EK.resize(52);
@@ -520,6 +529,7 @@ void AES_192::aesni_key_schedule(const byte key[], size_t)
 /*
 * AES-256 Encryption
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_256::aesni_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -608,6 +618,7 @@ void AES_256::aesni_encrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-256 Decryption
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_256::aesni_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -696,6 +707,7 @@ void AES_256::aesni_decrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-256 Key Schedule
 */
+BOTAN_FUNC_ISA("ssse3,aes")
 void AES_256::aesni_key_schedule(const byte key[], size_t)
    {
    m_EK.resize(60);
diff --git a/src/lib/block/aes_ssse3/aes_ssse3.cpp b/src/lib/block/aes_ssse3/aes_ssse3.cpp
index eda39a7cc..ef24795bb 100644
--- a/src/lib/block/aes_ssse3/aes_ssse3.cpp
+++ b/src/lib/block/aes_ssse3/aes_ssse3.cpp
@@ -51,6 +51,7 @@ const __m128i sr[4] = {
 
 #define mm_xor3(x, y, z) _mm_xor_si128(x, _mm_xor_si128(y, z))
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_transform(__m128i input,
                                __m128i table_1,
                                __m128i table_2)
@@ -63,6 +64,7 @@ __m128i aes_schedule_transform(__m128i input,
       _mm_shuffle_epi8(table_2, i_2));
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_mangle(__m128i k, byte round_no)
    {
    __m128i t = _mm_shuffle_epi8(_mm_xor_si128(k, _mm_set1_epi8(0x5B)),
@@ -77,6 +79,7 @@ __m128i aes_schedule_mangle(__m128i k, byte round_no)
    return _mm_shuffle_epi8(t2, sr[round_no % 4]);
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_192_smear(__m128i x, __m128i y)
    {
    return mm_xor3(y,
@@ -84,6 +87,7 @@ __m128i aes_schedule_192_smear(__m128i x, __m128i y)
                   _mm_shuffle_epi32(y, 0x80));
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_mangle_dec(__m128i k, byte round_no)
    {
    const __m128i dsk[8] = {
@@ -112,6 +116,7 @@ __m128i aes_schedule_mangle_dec(__m128i k, byte round_no)
    return _mm_shuffle_epi8(output, sr[round_no % 4]);
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_mangle_last(__m128i k, byte round_no)
    {
    const __m128i out_tr1 = _mm_set_epi32(
@@ -124,6 +129,7 @@ __m128i aes_schedule_mangle_last(__m128i k, byte round_no)
    return aes_schedule_transform(k, out_tr1, out_tr2);
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_mangle_last_dec(__m128i k)
    {
    const __m128i deskew1 = _mm_set_epi32(
@@ -135,6 +141,7 @@ __m128i aes_schedule_mangle_last_dec(__m128i k)
    return aes_schedule_transform(k, deskew1, deskew2);
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_schedule_round(__m128i* rcon, __m128i input1, __m128i input2)
    {
    if(rcon)
@@ -170,6 +177,7 @@ __m128i aes_schedule_round(__m128i* rcon, __m128i input1, __m128i input2)
                   smeared);
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_ssse3_encrypt(__m128i B, const __m128i* keys, size_t rounds)
    {
    const __m128i sb2u = _mm_set_epi32(
@@ -239,6 +247,7 @@ __m128i aes_ssse3_encrypt(__m128i B, const __m128i* keys, size_t rounds)
       }
    }
 
+BOTAN_FUNC_ISA("ssse3")
 __m128i aes_ssse3_decrypt(__m128i B, const __m128i* keys, size_t rounds)
    {
    const __m128i k_dipt1 = _mm_set_epi32(
@@ -336,6 +345,7 @@ __m128i aes_ssse3_decrypt(__m128i B, const __m128i* keys, size_t rounds)
 /*
 * AES-128 Encryption
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_128::ssse3_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -358,6 +368,7 @@ void AES_128::ssse3_encrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-128 Decryption
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_128::ssse3_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -380,6 +391,7 @@ void AES_128::ssse3_decrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-128 Key Schedule
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_128::ssse3_key_schedule(const byte keyb[], size_t)
    {
    __m128i rcon = _mm_set_epi32(0x702A9808, 0x4D7C7D81,
@@ -418,6 +430,7 @@ void AES_128::ssse3_key_schedule(const byte keyb[], size_t)
 /*
 * AES-192 Encryption
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_192::ssse3_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -440,6 +453,7 @@ void AES_192::ssse3_encrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-192 Decryption
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_192::ssse3_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -462,6 +476,7 @@ void AES_192::ssse3_decrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-192 Key Schedule
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_192::ssse3_key_schedule(const byte keyb[], size_t)
    {
    __m128i rcon = _mm_set_epi32(0x702A9808, 0x4D7C7D81,
@@ -529,6 +544,7 @@ void AES_192::ssse3_key_schedule(const byte keyb[], size_t)
 /*
 * AES-256 Encryption
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_256::ssse3_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -551,6 +567,7 @@ void AES_256::ssse3_encrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-256 Decryption
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_256::ssse3_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const __m128i* in_mm = reinterpret_cast<const __m128i*>(in);
@@ -573,6 +590,7 @@ void AES_256::ssse3_decrypt_n(const byte in[], byte out[], size_t blocks) const
 /*
 * AES-256 Key Schedule
 */
+BOTAN_FUNC_ISA("ssse3")
 void AES_256::ssse3_key_schedule(const byte keyb[], size_t)
    {
    __m128i rcon = _mm_set_epi32(0x702A9808, 0x4D7C7D81,
diff --git a/src/lib/block/idea_sse2/idea_sse2.cpp b/src/lib/block/idea_sse2/idea_sse2.cpp
index 4debfc95a..1e63a8332 100644
--- a/src/lib/block/idea_sse2/idea_sse2.cpp
+++ b/src/lib/block/idea_sse2/idea_sse2.cpp
@@ -13,6 +13,7 @@ namespace Botan {
 
 namespace {
 
+BOTAN_FUNC_ISA("sse2")
 inline __m128i mul(__m128i X, u16bit K_16)
    {
    const __m128i zeros = _mm_set1_epi16(0);
@@ -61,6 +62,7 @@ inline __m128i mul(__m128i X, u16bit K_16)
 * that extra unpack could easily save 3-4 cycles per block, and would
 * also help a lot with register pressure on 32-bit x86
 */
+BOTAN_FUNC_ISA("sse2")
 void transpose_in(__m128i& B0, __m128i& B1, __m128i& B2, __m128i& B3)
    {
    __m128i T0 = _mm_unpackhi_epi32(B0, B1);
@@ -97,6 +99,7 @@ void transpose_in(__m128i& B0, __m128i& B1, __m128i& B2, __m128i& B3)
 /*
 * 4x8 matrix transpose (reverse)
 */
+BOTAN_FUNC_ISA("sse2")
 void transpose_out(__m128i& B0, __m128i& B1, __m128i& B2, __m128i& B3)
    {
    __m128i T0 = _mm_unpacklo_epi64(B0, B1);
@@ -130,6 +133,7 @@ void transpose_out(__m128i& B0, __m128i& B1, __m128i& B2, __m128i& B3)
 /*
 * 8 wide IDEA encryption/decryption in SSE2
 */
+BOTAN_FUNC_ISA("sse2")
 void IDEA::sse2_idea_op_8(const byte in[64], byte out[64], const u16bit EK[52]) const
    {
    CT::poison(in, 64);
diff --git a/src/lib/block/threefish_avx2/threefish_avx2.cpp b/src/lib/block/threefish_avx2/threefish_avx2.cpp
index e0321812a..e4a46e3de 100644
--- a/src/lib/block/threefish_avx2/threefish_avx2.cpp
+++ b/src/lib/block/threefish_avx2/threefish_avx2.cpp
@@ -12,6 +12,7 @@ namespace Botan {
 
 namespace {
 
+BOTAN_FUNC_ISA("avx2")
 inline void interleave_epi64(__m256i& X0, __m256i& X1)
    {
    // interleave X0 and X1 qwords
@@ -24,6 +25,7 @@ inline void interleave_epi64(__m256i& X0, __m256i& X1)
    X1 = _mm256_permute4x64_epi64(T1, _MM_SHUFFLE(3,1,2,0));
    }
 
+BOTAN_FUNC_ISA("avx2")
 inline void deinterleave_epi64(__m256i& X0, __m256i& X1)
    {
    const __m256i T0 = _mm256_permute4x64_epi64(X0, _MM_SHUFFLE(3,1,2,0));
@@ -33,6 +35,7 @@ inline void deinterleave_epi64(__m256i& X0, __m256i& X1)
    X1 = _mm256_unpackhi_epi64(T0, T1);
    }
 
+BOTAN_FUNC_ISA("avx2")
 inline void rotate_keys(__m256i& R0, __m256i& R1, __m256i R2)
    {
    /*
@@ -71,6 +74,7 @@ inline void rotate_keys(__m256i& R0, __m256i& R1, __m256i R2)
 
 }
 
+BOTAN_FUNC_ISA("avx2")
 void Threefish_512::avx2_encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const u64bit* K = &get_K()[0];
@@ -245,6 +249,7 @@ void Threefish_512::avx2_encrypt_n(const byte in[], byte out[], size_t blocks) c
 #undef THREEFISH_INJECT_KEY_2
    }
 
+BOTAN_FUNC_ISA("avx2")
 void Threefish_512::avx2_decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
    const u64bit* K = &get_K()[0];
diff --git a/src/lib/cert/x509/certstor.cpp b/src/lib/cert/x509/certstor.cpp
index 28b46ef1a..24cd84de7 100644
--- a/src/lib/cert/x509/certstor.cpp
+++ b/src/lib/cert/x509/certstor.cpp
@@ -114,6 +114,7 @@ Certificate_Store_In_Memory::Certificate_Store_In_Memory(const X509_Certificate&
    add_certificate(cert);
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 Certificate_Store_In_Memory::Certificate_Store_In_Memory(const std::string& dir)
    {
    if(dir.empty())
@@ -131,6 +132,7 @@ Certificate_Store_In_Memory::Certificate_Store_In_Memory(const std::string& dir)
          }
       }
    }
+#endif
 
 std::shared_ptr<const X509_Certificate>
 Certificate_Store_Overlay::find_cert(const X509_DN& subject_dn,
diff --git a/src/lib/cert/x509/certstor_sql/certstor_sql.h b/src/lib/cert/x509/certstor_sql/certstor_sql.h
index c1168b827..0025884f9 100644
--- a/src/lib/cert/x509/certstor_sql/certstor_sql.h
+++ b/src/lib/cert/x509/certstor_sql/certstor_sql.h
@@ -97,7 +97,7 @@ class BOTAN_DLL Certificate_Store_In_SQL : public Certificate_Store
       std::shared_ptr<SQL_Database> m_database;
       std::string m_prefix;
       std::string m_password;
-      std::mutex m_mutex;
+      mutex_type m_mutex;
    };
 
 }
diff --git a/src/lib/cert/x509/pkcs10.cpp b/src/lib/cert/x509/pkcs10.cpp
index 40a9894cc..ccd22454b 100644
--- a/src/lib/cert/x509/pkcs10.cpp
+++ b/src/lib/cert/x509/pkcs10.cpp
@@ -25,14 +25,16 @@ PKCS10_Request::PKCS10_Request(DataSource& in) :
    do_decode();
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /*
 * PKCS10_Request Constructor
 */
-PKCS10_Request::PKCS10_Request(const std::string& in) :
-   X509_Object(in, "CERTIFICATE REQUEST/NEW CERTIFICATE REQUEST")
+PKCS10_Request::PKCS10_Request(const std::string& fsname) :
+   X509_Object(fsname, "CERTIFICATE REQUEST/NEW CERTIFICATE REQUEST")
    {
    do_decode();
    }
+#endif
 
 /*
 * PKCS10_Request Constructor
diff --git a/src/lib/cert/x509/pkcs10.h b/src/lib/cert/x509/pkcs10.h
index 8c9f49d84..c7a9ec300 100644
--- a/src/lib/cert/x509/pkcs10.h
+++ b/src/lib/cert/x509/pkcs10.h
@@ -86,12 +86,14 @@ class BOTAN_DLL PKCS10_Request final : public X509_Object
       */
       explicit PKCS10_Request(DataSource& source);
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
       /**
       * Create a PKCS#10 Request from a file.
       * @param filename the name of the file containing the DER or PEM
       * encoded request file
       */
       explicit PKCS10_Request(const std::string& filename);
+#endif
 
       /**
       * Create a PKCS#10 Request from binary data.
diff --git a/src/lib/cert/x509/x509_crl.cpp b/src/lib/cert/x509/x509_crl.cpp
index 3c75825c1..8eb4c01db 100644
--- a/src/lib/cert/x509/x509_crl.cpp
+++ b/src/lib/cert/x509/x509_crl.cpp
@@ -24,14 +24,16 @@ X509_CRL::X509_CRL(DataSource& in, bool touc) :
    do_decode();
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /*
 * Load a X.509 CRL
 */
-X509_CRL::X509_CRL(const std::string& in, bool touc) :
-   X509_Object(in, "CRL/X509 CRL"), m_throw_on_unknown_critical(touc)
+X509_CRL::X509_CRL(const std::string& fsname, bool touc) :
+   X509_Object(fsname, "CRL/X509 CRL"), m_throw_on_unknown_critical(touc)
    {
    do_decode();
    }
+#endif
 
 X509_CRL::X509_CRL(const std::vector<byte>& in, bool touc) :
    X509_Object(in, "CRL/X509 CRL"), m_throw_on_unknown_critical(touc)
diff --git a/src/lib/cert/x509/x509_crl.h b/src/lib/cert/x509/x509_crl.h
index 7373e9936..e11ea8f48 100644
--- a/src/lib/cert/x509/x509_crl.h
+++ b/src/lib/cert/x509/x509_crl.h
@@ -82,6 +82,7 @@ class BOTAN_DLL X509_CRL final : public X509_Object
       */
       X509_CRL(DataSource& source, bool throw_on_unknown_critical = false);
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
       /**
       * Construct a CRL from a file containing the DER or PEM encoded CRL.
       * @param filename the name of the CRL file
@@ -90,6 +91,7 @@ class BOTAN_DLL X509_CRL final : public X509_Object
       */
       X509_CRL(const std::string& filename,
                bool throw_on_unknown_critical = false);
+#endif
 
       /**
       * Construct a CRL from a binary vector
diff --git a/src/lib/cert/x509/x509_obj.cpp b/src/lib/cert/x509/x509_obj.cpp
index 983be40b2..3c5d2a9b4 100644
--- a/src/lib/cert/x509/x509_obj.cpp
+++ b/src/lib/cert/x509/x509_obj.cpp
@@ -25,6 +25,7 @@ X509_Object::X509_Object(DataSource& stream, const std::string& labels)
    init(stream, labels);
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /*
 * Create a generic X.509 object
 */
@@ -33,6 +34,7 @@ X509_Object::X509_Object(const std::string& file, const std::string& labels)
    DataSource_Stream stream(file, true);
    init(stream, labels);
    }
+#endif
 
 /*
 * Create a generic X.509 object
diff --git a/src/lib/cert/x509/x509_obj.h b/src/lib/cert/x509/x509_obj.h
index 8b561a142..40324775c 100644
--- a/src/lib/cert/x509/x509_obj.h
+++ b/src/lib/cert/x509/x509_obj.h
@@ -96,9 +96,12 @@ class BOTAN_DLL X509_Object : public ASN1_Object
       virtual ~X509_Object() {}
    protected:
       X509_Object(DataSource& src, const std::string& pem_labels);
-      X509_Object(const std::string& file, const std::string& pem_labels);
       X509_Object(const std::vector<byte>& vec, const std::string& labels);
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+      X509_Object(const std::string& file, const std::string& pem_labels);
+#endif
+
       void do_decode();
       X509_Object() {}
       AlgorithmIdentifier m_sig_algo;
diff --git a/src/lib/cert/x509/x509cert.cpp b/src/lib/cert/x509/x509cert.cpp
index 5765214ae..f56495a79 100644
--- a/src/lib/cert/x509/x509cert.cpp
+++ b/src/lib/cert/x509/x509cert.cpp
@@ -50,16 +50,18 @@ X509_Certificate::X509_Certificate(DataSource& in) :
    do_decode();
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /*
 * X509_Certificate Constructor
 */
-X509_Certificate::X509_Certificate(const std::string& in) :
-   X509_Object(in, "CERTIFICATE/X509 CERTIFICATE"),
+X509_Certificate::X509_Certificate(const std::string& fsname) :
+   X509_Object(fsname, "CERTIFICATE/X509 CERTIFICATE"),
    m_self_signed(false),
    m_v3_extensions(false)
    {
    do_decode();
    }
+#endif
 
 /*
 * X509_Certificate Constructor
diff --git a/src/lib/cert/x509/x509cert.h b/src/lib/cert/x509/x509cert.h
index 12e99c44e..acdba7e02 100644
--- a/src/lib/cert/x509/x509cert.h
+++ b/src/lib/cert/x509/x509cert.h
@@ -267,12 +267,14 @@ class BOTAN_DLL X509_Certificate : public X509_Object
       */
       explicit X509_Certificate(DataSource& source);
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
       /**
       * Create a certificate from a file containing the DER or PEM
       * encoded certificate.
       * @param filename the name of the certificate file
       */
       explicit X509_Certificate(const std::string& filename);
+#endif
 
       /**
       * Create a certificate from a buffer
diff --git a/src/lib/cert/x509/x509path.cpp b/src/lib/cert/x509/x509path.cpp
index 65ab3eac1..29853bb4a 100644
--- a/src/lib/cert/x509/x509path.cpp
+++ b/src/lib/cert/x509/x509path.cpp
@@ -15,6 +15,7 @@
 #include <chrono>
 #include <vector>
 #include <set>
+#include <future>
 
 namespace Botan {
 
diff --git a/src/lib/entropy/egd/es_egd.cpp b/src/lib/entropy/egd/es_egd.cpp
index 384516aa8..fdc1c9a0f 100644
--- a/src/lib/entropy/egd/es_egd.cpp
+++ b/src/lib/entropy/egd/es_egd.cpp
@@ -136,7 +136,7 @@ EGD_EntropySource::~EGD_EntropySource()
 */
 size_t EGD_EntropySource::poll(RandomNumberGenerator& rng)
    {
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    secure_vector<byte> buf(BOTAN_SYSTEM_RNG_POLL_REQUEST);
 
diff --git a/src/lib/entropy/egd/es_egd.h b/src/lib/entropy/egd/es_egd.h
index 04b4591e3..e0fb9c2d5 100644
--- a/src/lib/entropy/egd/es_egd.h
+++ b/src/lib/entropy/egd/es_egd.h
@@ -11,7 +11,7 @@
 #include <botan/entropy_src.h>
 #include <string>
 #include <vector>
-#include <mutex>
+#include <botan/mutex.h>
 
 namespace Botan {
 
@@ -42,7 +42,7 @@ class EGD_EntropySource final : public Entropy_Source
             int m_fd; // cached fd
          };
 
-      std::mutex m_mutex;
+      mutex_type m_mutex;
       std::vector<EGD_Socket> m_sockets;
       secure_vector<uint8_t> m_io_buf;
    };
diff --git a/src/lib/entropy/proc_walk/proc_walk.cpp b/src/lib/entropy/proc_walk/proc_walk.cpp
index beaa57308..5132ac951 100644
--- a/src/lib/entropy/proc_walk/proc_walk.cpp
+++ b/src/lib/entropy/proc_walk/proc_walk.cpp
@@ -114,7 +114,7 @@ size_t ProcWalking_EntropySource::poll(RandomNumberGenerator& rng)
    {
    const size_t MAX_FILES_READ_PER_POLL = 2048;
 
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    if(!m_dir)
       m_dir.reset(new Directory_Walker(m_path));
diff --git a/src/lib/entropy/proc_walk/proc_walk.h b/src/lib/entropy/proc_walk/proc_walk.h
index 369b52699..4e9562c88 100644
--- a/src/lib/entropy/proc_walk/proc_walk.h
+++ b/src/lib/entropy/proc_walk/proc_walk.h
@@ -9,7 +9,7 @@
 #define BOTAN_ENTROPY_SRC_PROC_WALK_H__
 
 #include <botan/entropy_src.h>
-#include <mutex>
+#include <botan/mutex.h>
 
 namespace Botan {
 
@@ -35,7 +35,7 @@ class ProcWalking_EntropySource final : public Entropy_Source
 
    private:
       const std::string m_path;
-      std::mutex m_mutex;
+      mutex_type m_mutex;
       std::unique_ptr<File_Descriptor_Source> m_dir;
       secure_vector<byte> m_buf;
    };
diff --git a/src/lib/entropy/rdseed/rdseed.cpp b/src/lib/entropy/rdseed/rdseed.cpp
index 325edfd41..01cab3a7e 100644
--- a/src/lib/entropy/rdseed/rdseed.cpp
+++ b/src/lib/entropy/rdseed/rdseed.cpp
@@ -15,6 +15,7 @@
 
 namespace Botan {
 
+BOTAN_FUNC_ISA("rdseed")
 size_t Intel_Rdseed::poll(RandomNumberGenerator& rng) {
    if(CPUID::has_rdseed())
       {
diff --git a/src/lib/entropy/unix_procs/unix_procs.cpp b/src/lib/entropy/unix_procs/unix_procs.cpp
index 8f885cfcf..d8dceba52 100644
--- a/src/lib/entropy/unix_procs/unix_procs.cpp
+++ b/src/lib/entropy/unix_procs/unix_procs.cpp
@@ -209,7 +209,7 @@ size_t Unix_EntropySource::poll(RandomNumberGenerator& rng)
    if((getuid() != geteuid()) || (getgid() != getegid()) || (geteuid() == 0))
       return 0;
 
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    if(m_sources.empty())
       {
diff --git a/src/lib/entropy/unix_procs/unix_procs.h b/src/lib/entropy/unix_procs/unix_procs.h
index 27f7ab5bb..f87881d54 100644
--- a/src/lib/entropy/unix_procs/unix_procs.h
+++ b/src/lib/entropy/unix_procs/unix_procs.h
@@ -10,7 +10,7 @@
 
 #include <botan/entropy_src.h>
 #include <vector>
-#include <mutex>
+#include <botan/mutex.h>
 
 namespace Botan {
 
@@ -67,7 +67,7 @@ class Unix_EntropySource final : public Entropy_Source
 
       const std::vector<std::string>& next_source();
 
-      std::mutex m_mutex;
+      mutex_type m_mutex;
       const std::vector<std::string> m_trusted_paths;
       const size_t m_concurrent;
 
diff --git a/src/lib/ffi/ffi.cpp b/src/lib/ffi/ffi.cpp
index cc27f485a..aaa89ff5d 100644
--- a/src/lib/ffi/ffi.cpp
+++ b/src/lib/ffi/ffi.cpp
@@ -1211,6 +1211,7 @@ int botan_x509_cert_load_file(botan_x509_cert_t* cert_obj, const char* cert_path
       if(!cert_obj || !cert_path)
          return -1;
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
       std::unique_ptr<Botan::X509_Certificate> c(new Botan::X509_Certificate(cert_path));
 
       if(c)
@@ -1218,6 +1219,9 @@ int botan_x509_cert_load_file(botan_x509_cert_t* cert_obj, const char* cert_path
          *cert_obj = new botan_x509_cert_struct(c.release());
          return 0;
          }
+#else
+      return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
+#endif
       }
    catch(std::exception& e)
       {
diff --git a/src/lib/filters/basefilt.h b/src/lib/filters/basefilt.h
index c065fae0e..d803542a1 100644
--- a/src/lib/filters/basefilt.h
+++ b/src/lib/filters/basefilt.h
@@ -10,7 +10,10 @@
 #define BOTAN_BASEFILT_H__
 
 #include <botan/filter.h>
+
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
 #include <thread>
+#endif
 
 namespace Botan {
 
@@ -78,6 +81,8 @@ class BOTAN_DLL Fork : public Fanout_Filter
       Fork(Filter* filter_arr[], size_t length);
    };
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+
 /**
 * This class is a threaded version of the Fork filter. While this uses
 * threads, the class itself is NOT thread-safe. This is meant as a drop-
@@ -113,6 +118,7 @@ class BOTAN_DLL Threaded_Fork : public Fork
       std::vector<std::shared_ptr<std::thread>> m_threads;
       std::unique_ptr<struct Threaded_Fork_Data> m_thread_data;
    };
+#endif
 
 }
 
diff --git a/src/lib/filters/data_snk.cpp b/src/lib/filters/data_snk.cpp
index df35b12bf..efedef268 100644
--- a/src/lib/filters/data_snk.cpp
+++ b/src/lib/filters/data_snk.cpp
@@ -8,10 +8,14 @@
 
 #include <botan/data_snk.h>
 #include <botan/exceptn.h>
-#include <fstream>
+
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+  #include <fstream>
+#endif
 
 namespace Botan {
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /*
 * Write to a stream
 */
@@ -58,5 +62,6 @@ DataSink_Stream::~DataSink_Stream()
    {
    delete m_sink_p;
    }
+#endif
 
 }
diff --git a/src/lib/filters/data_snk.h b/src/lib/filters/data_snk.h
index 56b292e46..2405fdf98 100644
--- a/src/lib/filters/data_snk.h
+++ b/src/lib/filters/data_snk.h
@@ -27,6 +27,8 @@ class BOTAN_DLL DataSink : public Filter
       DataSink(const DataSink&) = delete;
    };
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+
 /**
 * This class represents a data sink which writes its output to a stream.
 */
@@ -62,6 +64,8 @@ class BOTAN_DLL DataSink_Stream : public DataSink
       std::ostream& m_sink;
    };
 
+#endif
+
 }
 
 #endif
diff --git a/src/lib/filters/threaded_fork.cpp b/src/lib/filters/threaded_fork.cpp
index 5ee802593..f558ac9c2 100644
--- a/src/lib/filters/threaded_fork.cpp
+++ b/src/lib/filters/threaded_fork.cpp
@@ -7,6 +7,9 @@
 */
 
 #include <botan/basefilt.h>
+
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+
 #include <botan/internal/semaphore.h>
 
 namespace Botan {
@@ -144,3 +147,5 @@ void Threaded_Fork::thread_entry(Filter* filter)
    }
 
 }
+
+#endif
diff --git a/src/lib/hash/sha1_sse2/sha1_sse2.cpp b/src/lib/hash/sha1_sse2/sha1_sse2.cpp
index 2ece541b0..0f88bb4c2 100644
--- a/src/lib/hash/sha1_sse2/sha1_sse2.cpp
+++ b/src/lib/hash/sha1_sse2/sha1_sse2.cpp
@@ -152,6 +152,7 @@ inline void F4(u32bit A, u32bit& B, u32bit C, u32bit D, u32bit& E, u32bit msg)
 * SHA-160 Compression Function using SSE for message expansion
 */
 //static
+BOTAN_FUNC_ISA("sse2")
 void SHA_160::sse2_compress_n(secure_vector<uint32_t>& digest, const byte input[], size_t blocks)
    {
    using namespace SHA1_SSE2_F;
diff --git a/src/lib/misc/srp6/srp6_files.cpp b/src/lib/misc/srp6/srp6_files.cpp
index 14ab1ac61..606c12ad7 100644
--- a/src/lib/misc/srp6/srp6_files.cpp
+++ b/src/lib/misc/srp6/srp6_files.cpp
@@ -8,14 +8,11 @@
 #include <botan/srp6_files.h>
 #include <botan/parsing.h>
 #include <botan/base64.h>
-#include <fstream>
 
 namespace Botan {
 
-SRP6_Authenticator_File::SRP6_Authenticator_File(const std::string& filename)
+SRP6_Authenticator_File::SRP6_Authenticator_File(std::istream& in)
    {
-   std::ifstream in(filename);
-
    if(!in)
       return; // no entries
 
diff --git a/src/lib/misc/srp6/srp6_files.h b/src/lib/misc/srp6/srp6_files.h
index 2b20de7a3..db128727e 100644
--- a/src/lib/misc/srp6/srp6_files.h
+++ b/src/lib/misc/srp6/srp6_files.h
@@ -9,6 +9,7 @@
 #define BOTAN_SRP6A_FILES_H__
 
 #include <botan/bigint.h>
+#include <iosfwd>
 #include <string>
 #include <map>
 
@@ -20,11 +21,11 @@ namespace Botan {
 class BOTAN_DLL SRP6_Authenticator_File
    {
    public:
+
       /**
-      * @param filename will be opened and processed as a SRP
-      * authenticator file
+      * @param input will be read and processed as SRP authenticator file
       */
-      explicit SRP6_Authenticator_File(const std::string& filename);
+      explicit SRP6_Authenticator_File(std::istream& input);
 
       bool lookup_user(const std::string& username,
                        BigInt& v,
diff --git a/src/lib/modes/aead/gcm/clmul/clmul.cpp b/src/lib/modes/aead/gcm/clmul/clmul.cpp
index 6e1db7012..725ef3da3 100644
--- a/src/lib/modes/aead/gcm/clmul/clmul.cpp
+++ b/src/lib/modes/aead/gcm/clmul/clmul.cpp
@@ -11,6 +11,7 @@
 
 namespace Botan {
 
+BOTAN_FUNC_ISA("pclmul,ssse3")
 void gcm_multiply_clmul(byte x[16], const byte H[16])
    {
    /*
diff --git a/src/lib/pubkey/dsa/dsa.cpp b/src/lib/pubkey/dsa/dsa.cpp
index 15dc45373..9c8ae0821 100644
--- a/src/lib/pubkey/dsa/dsa.cpp
+++ b/src/lib/pubkey/dsa/dsa.cpp
@@ -17,7 +17,9 @@
   #include <botan/rfc6979.h>
 #endif
 
-#include <future>
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+  #include <future>
+#endif
 
 namespace Botan {
 
@@ -124,11 +126,17 @@ DSA_Signature_Operation::raw_sign(const byte msg[], size_t msg_len,
    const BigInt k = BigInt::random_integer(rng, 1, m_q);
 #endif
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
    auto future_r = std::async(std::launch::async,
                               [&]() { return m_mod_q.reduce(m_powermod_g_p(k)); });
 
    BigInt s = inverse_mod(k, m_q);
    const BigInt r = future_r.get();
+#else
+   BigInt s = inverse_mod(k, m_q);
+   const BigInt r = m_mod_q.reduce(m_powermod_g_p(k));
+#endif
+
    s = m_mod_q.multiply(s, mul_add(m_x, r, i));
 
    // With overwhelming probability, a bug rather than actual zero r/s
@@ -184,11 +192,16 @@ bool DSA_Verification_Operation::verify(const byte msg[], size_t msg_len,
 
    s = inverse_mod(s, m_q);
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
    auto future_s_i = std::async(std::launch::async,
       [&]() { return m_powermod_g_p(m_mod_q.multiply(s, i)); });
 
    BigInt s_r = m_powermod_y_p(m_mod_q.multiply(s, r));
    BigInt s_i = future_s_i.get();
+#else
+   BigInt s_r = m_powermod_y_p(m_mod_q.multiply(s, r));
+   BigInt s_i = m_powermod_g_p(m_mod_q.multiply(s, i));
+#endif
 
    s = m_mod_p.multiply(s_i, s_r);
 
diff --git a/src/lib/pubkey/pkcs8.cpp b/src/lib/pubkey/pkcs8.cpp
index ddf9be2f0..96dfd5e44 100644
--- a/src/lib/pubkey/pkcs8.cpp
+++ b/src/lib/pubkey/pkcs8.cpp
@@ -262,6 +262,8 @@ Private_Key* load_key(DataSource& source,
       throw PKCS8_Exception( "Internal error: Attempt to read password for unencrypted key" );}, false);
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+
 /*
 * Extract an encrypted private key and return it
 */
@@ -293,6 +295,7 @@ Private_Key* load_key(const std::string& fsname,
    return load_key(source, rng, []() -> std::string {
       throw PKCS8_Exception( "Internal error: Attempt to read password for unencrypted key" );}, false);
    }
+#endif
 
 /*
 * Make a copy of this private key
diff --git a/src/lib/pubkey/pkcs8.h b/src/lib/pubkey/pkcs8.h
index 791a612df..9cc350285 100644
--- a/src/lib/pubkey/pkcs8.h
+++ b/src/lib/pubkey/pkcs8.h
@@ -108,6 +108,7 @@ BOTAN_DLL Private_Key* load_key(DataSource& source,
 BOTAN_DLL Private_Key* load_key(DataSource& source,
                                 RandomNumberGenerator& rng);
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /**
 * Load an encrypted key from a file.
 * @param filename the path to the file containing the encoded key
@@ -136,6 +137,7 @@ BOTAN_DLL Private_Key* load_key(const std::string& filename,
 */
 BOTAN_DLL Private_Key* load_key(const std::string& filename,
                                 RandomNumberGenerator& rng);
+#endif
 
 /**
 * Copy an existing encoded key object.
diff --git a/src/lib/pubkey/rsa/rsa.cpp b/src/lib/pubkey/rsa/rsa.cpp
index b40f485e3..d201ca277 100644
--- a/src/lib/pubkey/rsa/rsa.cpp
+++ b/src/lib/pubkey/rsa/rsa.cpp
@@ -14,12 +14,16 @@
 #include <botan/workfactor.h>
 #include <botan/der_enc.h>
 #include <botan/ber_dec.h>
-#include <future>
 
 #if defined(BOTAN_HAS_OPENSSL)
   #include <botan/internal/openssl.h>
 #endif
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+#include <future>
+#endif
+
+
 namespace Botan {
 
 size_t RSA_PublicKey::estimated_strength() const
@@ -218,9 +222,14 @@ class RSA_Private_Operation
 
       BigInt private_op(const BigInt& m) const
          {
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
          auto future_j1 = std::async(std::launch::async, m_powermod_d1_p, m);
          BigInt j2 = m_powermod_d2_q(m);
          BigInt j1 = future_j1.get();
+#else
+         BigInt j1 = m_powermod_d1_p(m);
+         BigInt j2 = m_powermod_d2_q(m);
+#endif
 
          j1 = m_mod_p.reduce(sub_mul(j1, j2, m_c));
 
diff --git a/src/lib/pubkey/x509_key.cpp b/src/lib/pubkey/x509_key.cpp
index ccb94cea7..08e17bfed 100644
--- a/src/lib/pubkey/x509_key.cpp
+++ b/src/lib/pubkey/x509_key.cpp
@@ -78,6 +78,7 @@ Public_Key* load_key(DataSource& source)
       }
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /*
 * Extract a public key and return it
 */
@@ -86,6 +87,7 @@ Public_Key* load_key(const std::string& fsname)
    DataSource_Stream source(fsname, true);
    return X509::load_key(source);
    }
+#endif
 
 /*
 * Extract a public key and return it
diff --git a/src/lib/pubkey/x509_key.h b/src/lib/pubkey/x509_key.h
index cbb0412d2..7162b338e 100644
--- a/src/lib/pubkey/x509_key.h
+++ b/src/lib/pubkey/x509_key.h
@@ -46,12 +46,14 @@ BOTAN_DLL std::string PEM_encode(const Public_Key& key);
 */
 BOTAN_DLL Public_Key* load_key(DataSource& source);
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 /**
 * Create a public key from a file
 * @param filename pathname to the file to load
 * @return new public key object
 */
 BOTAN_DLL Public_Key* load_key(const std::string& filename);
+#endif
 
 /**
 * Create a public key from a memory region.
diff --git a/src/lib/rng/rdrand_rng/rdrand_rng.cpp b/src/lib/rng/rdrand_rng/rdrand_rng.cpp
index 4d2e51cf8..1ee857c6c 100644
--- a/src/lib/rng/rdrand_rng/rdrand_rng.cpp
+++ b/src/lib/rng/rdrand_rng/rdrand_rng.cpp
@@ -36,6 +36,7 @@ uint32_t RDRAND_RNG::rdrand()
    }
 
 //static
+BOTAN_FUNC_ISA("rdrnd")
 uint32_t RDRAND_RNG::rdrand_status(bool& ok)
    {
    ok = false;
diff --git a/src/lib/rng/rng.cpp b/src/lib/rng/rng.cpp
index 8c2982312..a2dd3d3a4 100644
--- a/src/lib/rng/rng.cpp
+++ b/src/lib/rng/rng.cpp
@@ -57,6 +57,8 @@ RandomNumberGenerator* RandomNumberGenerator::make_rng()
 #endif
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
 Serialized_RNG::Serialized_RNG() : m_rng(RandomNumberGenerator::make_rng()) {}
+#endif
 
 }
diff --git a/src/lib/rng/rng.h b/src/lib/rng/rng.h
index d1cdcfff2..e3640a32f 100644
--- a/src/lib/rng/rng.h
+++ b/src/lib/rng/rng.h
@@ -11,9 +11,9 @@
 #include <botan/entropy_src.h>
 #include <botan/secmem.h>
 #include <botan/exceptn.h>
+#include <botan/mutex.h>
 #include <chrono>
 #include <string>
-#include <mutex>
 
 namespace Botan {
 
@@ -193,6 +193,7 @@ class BOTAN_DLL Null_RNG final : public RandomNumberGenerator
       std::string name() const override { return "Null_RNG"; }
    };
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
 /**
 * Wraps access to a RNG in a mutex
 */
@@ -201,25 +202,25 @@ class BOTAN_DLL Serialized_RNG final : public RandomNumberGenerator
    public:
       void randomize(byte out[], size_t len) override
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          m_rng->randomize(out, len);
          }
 
       bool is_seeded() const override
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          return m_rng->is_seeded();
          }
 
       void clear() override
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          m_rng->clear();
          }
 
       std::string name() const override
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          return m_rng->name();
          }
 
@@ -227,23 +228,24 @@ class BOTAN_DLL Serialized_RNG final : public RandomNumberGenerator
                     size_t poll_bits = BOTAN_RNG_RESEED_POLL_BITS,
                     std::chrono::milliseconds poll_timeout = BOTAN_RNG_RESEED_DEFAULT_TIMEOUT) override
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          return m_rng->reseed(src, poll_bits, poll_timeout);
          }
 
       void add_entropy(const byte in[], size_t len) override
          {
-         std::lock_guard<std::mutex> lock(m_mutex);
+         lock_guard_type<mutex_type> lock(m_mutex);
          m_rng->add_entropy(in, len);
          }
 
-      BOTAN_DEPRECATED("Create an AutoSeeded_RNG for other constructor") Serialized_RNG();
+      BOTAN_DEPRECATED("Use Serialized_RNG(new AutoSeeded_RNG)") Serialized_RNG();
 
       explicit Serialized_RNG(RandomNumberGenerator* rng) : m_rng(rng) {}
    private:
-      mutable std::mutex m_mutex;
+      mutable mutex_type m_mutex;
       std::unique_ptr<RandomNumberGenerator> m_rng;
    };
+#endif
 
 }
 
diff --git a/src/lib/stream/chacha/chacha_sse2/chacha_sse2.cpp b/src/lib/stream/chacha/chacha_sse2/chacha_sse2.cpp
index e39b285b3..a7261a522 100644
--- a/src/lib/stream/chacha/chacha_sse2/chacha_sse2.cpp
+++ b/src/lib/stream/chacha/chacha_sse2/chacha_sse2.cpp
@@ -11,6 +11,7 @@
 namespace Botan {
 
 //static
+BOTAN_FUNC_ISA("sse2")
 void ChaCha::chacha_sse2_x4(byte output[64], u32bit input[16], size_t rounds)
    {
    BOTAN_ASSERT(rounds % 2 == 0, "Valid rounds");
diff --git a/src/lib/tls/tls_session_manager.h b/src/lib/tls/tls_session_manager.h
index e01462f66..49f4925d8 100644
--- a/src/lib/tls/tls_session_manager.h
+++ b/src/lib/tls/tls_session_manager.h
@@ -9,7 +9,7 @@
 #define BOTAN_TLS_SESSION_MANAGER_H__
 
 #include <botan/tls_session.h>
-#include <mutex>
+#include <botan/mutex.h>
 #include <chrono>
 #include <map>
 
@@ -138,7 +138,7 @@ class BOTAN_DLL Session_Manager_In_Memory : public Session_Manager
       bool load_from_session_str(const std::string& session_str,
                                  Session& session);
 
-      std::mutex m_mutex;
+      mutex_type m_mutex;
 
       size_t m_max_sessions;
 
diff --git a/src/lib/tls/tls_session_manager_memory.cpp b/src/lib/tls/tls_session_manager_memory.cpp
index 37019c943..d0866b37a 100644
--- a/src/lib/tls/tls_session_manager_memory.cpp
+++ b/src/lib/tls/tls_session_manager_memory.cpp
@@ -57,7 +57,7 @@ bool Session_Manager_In_Memory::load_from_session_str(
 bool Session_Manager_In_Memory::load_from_session_id(
    const std::vector<byte>& session_id, Session& session)
    {
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    return load_from_session_str(hex_encode(session_id), session);
    }
@@ -65,7 +65,7 @@ bool Session_Manager_In_Memory::load_from_session_id(
 bool Session_Manager_In_Memory::load_from_server_info(
    const Server_Information& info, Session& session)
    {
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    auto i = m_info_sessions.find(info);
 
@@ -87,7 +87,7 @@ bool Session_Manager_In_Memory::load_from_server_info(
 void Session_Manager_In_Memory::remove_entry(
    const std::vector<byte>& session_id)
    {
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    auto i = m_sessions.find(hex_encode(session_id));
 
@@ -106,7 +106,7 @@ size_t Session_Manager_In_Memory::remove_all()
 
 void Session_Manager_In_Memory::save(const Session& session)
    {
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    if(m_max_sessions != 0)
       {
diff --git a/src/lib/utils/calendar.cpp b/src/lib/utils/calendar.cpp
index 2ed90486a..4f6c835d1 100644
--- a/src/lib/utils/calendar.cpp
+++ b/src/lib/utils/calendar.cpp
@@ -11,7 +11,7 @@
 #include <ctime>
 #include <sstream>
 #include <iomanip>
-#include <mutex>
+#include <botan/mutex.h>
 #include <stdlib.h>
 
 #if defined(BOTAN_HAS_BOOST_DATETIME)
@@ -72,7 +72,7 @@ std::time_t boost_timegm(std::tm *tm)
 
 #pragma message "Caution! A fallback version of timegm() is used which is not thread-safe"
 
-std::mutex ENV_TZ;
+mutex_type ENV_TZ;
 
 std::time_t fallback_timegm(std::tm *tm)
    {
diff --git a/src/lib/utils/data_src.cpp b/src/lib/utils/data_src.cpp
index 0c06f2fe4..7da94d7c0 100644
--- a/src/lib/utils/data_src.cpp
+++ b/src/lib/utils/data_src.cpp
@@ -8,9 +8,12 @@
 
 #include <botan/data_src.h>
 #include <botan/exceptn.h>
-#include <fstream>
 #include <algorithm>
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+  #include <fstream>
+#endif
+
 namespace Botan {
 
 /*
@@ -98,6 +101,8 @@ DataSource_Memory::DataSource_Memory(const std::string& in) :
    {
    }
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+
 /*
 * Read from a stream
 */
@@ -209,4 +214,6 @@ DataSource_Stream::~DataSource_Stream()
    delete m_source_p;
    }
 
+#endif
+
 }
diff --git a/src/lib/utils/data_src.h b/src/lib/utils/data_src.h
index 6a100ce63..b24fd75a4 100644
--- a/src/lib/utils/data_src.h
+++ b/src/lib/utils/data_src.h
@@ -138,6 +138,8 @@ class BOTAN_DLL DataSource_Memory : public DataSource
       size_t m_offset;
    };
 
+#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
+
 /**
 * This class represents a Stream-Based DataSource.
 */
@@ -175,6 +177,8 @@ class BOTAN_DLL DataSource_Stream : public DataSource
       size_t m_total_read;
    };
 
+#endif
+
 }
 
 #endif
diff --git a/src/lib/utils/http_util/http_util.cpp b/src/lib/utils/http_util/http_util.cpp
index 1286e4026..5624f2e4f 100644
--- a/src/lib/utils/http_util/http_util.cpp
+++ b/src/lib/utils/http_util/http_util.cpp
@@ -226,11 +226,6 @@ Response POST_sync(const std::string& url,
    return http_sync("POST", url, content_type, body, allowable_redirects);
    }
 
-std::future<Response> GET_async(const std::string& url, size_t allowable_redirects)
-   {
-   return std::async(std::launch::async, GET_sync, url, allowable_redirects);
-   }
-
 }
 
 }
diff --git a/src/lib/utils/http_util/http_util.h b/src/lib/utils/http_util/http_util.h
index 6688285c6..918dfc269 100644
--- a/src/lib/utils/http_util/http_util.h
+++ b/src/lib/utils/http_util/http_util.h
@@ -10,7 +10,6 @@
 
 #include <botan/types.h>
 #include <botan/exceptn.h>
-#include <future>
 #include <vector>
 #include <map>
 #include <chrono>
@@ -88,9 +87,6 @@ BOTAN_DLL Response POST_sync(const std::string& url,
                              const std::vector<byte>& body,
                              size_t allowable_redirects = 1);
 
-std::future<Response> BOTAN_DLL GET_async(const std::string& url,
-                                                    size_t allowable_redirects = 1);
-
 BOTAN_DLL std::string url_encode(const std::string& url);
 
 }
diff --git a/src/lib/utils/info.txt b/src/lib/utils/info.txt
index 511e6b0e8..189b2da1f 100644
--- a/src/lib/utils/info.txt
+++ b/src/lib/utils/info.txt
@@ -14,6 +14,7 @@ exceptn.h
 loadstor.h
 mem_ops.h
 mul128.h
+mutex.h
 parsing.h
 rotate.h
 types.h
diff --git a/src/lib/utils/locking_allocator/locking_allocator.cpp b/src/lib/utils/locking_allocator/locking_allocator.cpp
index c6181d4c0..770464d92 100644
--- a/src/lib/utils/locking_allocator/locking_allocator.cpp
+++ b/src/lib/utils/locking_allocator/locking_allocator.cpp
@@ -11,7 +11,7 @@
 #include <algorithm>
 #include <cstdlib>
 #include <string>
-#include <mutex>
+#include <botan/mutex.h>
 
 namespace Botan {
 
@@ -58,7 +58,7 @@ void* mlock_allocator::allocate(size_t num_elems, size_t elem_size)
    if(n < BOTAN_MLOCK_ALLOCATOR_MIN_ALLOCATION || n > BOTAN_MLOCK_ALLOCATOR_MAX_ALLOCATION)
       return nullptr;
 
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    auto best_fit = m_freelist.end();
 
@@ -146,7 +146,7 @@ bool mlock_allocator::deallocate(void* p, size_t num_elems, size_t elem_size)
    if(!ptr_in_pool(m_pool, m_poolsize, p, n))
       return false;
 
-   std::lock_guard<std::mutex> lock(m_mutex);
+   lock_guard_type<mutex_type> lock(m_mutex);
 
    const size_t start = static_cast<byte*>(p) - m_pool;
 
diff --git a/src/lib/utils/locking_allocator/locking_allocator.h b/src/lib/utils/locking_allocator/locking_allocator.h
index db75bc02a..5c19852c0 100644
--- a/src/lib/utils/locking_allocator/locking_allocator.h
+++ b/src/lib/utils/locking_allocator/locking_allocator.h
@@ -10,7 +10,7 @@
 
 #include <botan/types.h>
 #include <vector>
-#include <mutex>
+#include <botan/mutex.h>
 
 namespace Botan {
 
@@ -32,7 +32,7 @@ class BOTAN_DLL mlock_allocator
 
       ~mlock_allocator();
 
-      std::mutex m_mutex;
+      mutex_type m_mutex;
       std::vector<std::pair<size_t, size_t>> m_freelist;
       byte* m_pool = nullptr;
       size_t m_poolsize = 0;
diff --git a/src/lib/utils/mutex.h b/src/lib/utils/mutex.h
new file mode 100644
index 000000000..0daea3148
--- /dev/null
+++ b/src/lib/utils/mutex.h
@@ -0,0 +1,61 @@
+/*
+* (C) 2016 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_UTIL_MUTEX_H__
+#define BOTAN_UTIL_MUTEX_H__
+
+#include <botan/build.h>
+#include <botan/types.h>
+
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+
+#include <mutex>
+
+namespace Botan {
+
+template<typename T> using lock_guard_type = std::lock_guard<T>;
+typedef std::mutex mutex_type;
+
+}
+
+#elif defined(BOTAN_TARGET_OS_TYPE_IS_UNIKERNEL)
+
+// No threads
+
+namespace Botan {
+
+template<typename Mutex>
+class lock_guard
+   {
+   public:
+      explicit lock_guard(Mutex& m) : m_mutex(m)
+         { m_mutex.lock(); }
+
+      ~lock_guard() { m_mutex.unlock(); }
+
+      lock_guard(const lock_guard& other) = delete;
+      lock_guard& operator=(const lock_guard& other) = delete;
+   private:
+      Mutex& m_mutex;
+   };
+
+class noop_mutex
+   {
+   public:
+      void lock() {}
+      void unlock() {}
+   };
+
+typedef noop_mutex mutex_type;
+template<typename T> using lock_guard_type = lock_guard<T>;
+
+}
+
+#else
+  #error "Threads unexpectedly disabled in non unikernel build"
+#endif
+
+#endif
diff --git a/src/lib/utils/os_utils.cpp b/src/lib/utils/os_utils.cpp
index 2f17da952..4020a4be3 100644
--- a/src/lib/utils/os_utils.cpp
+++ b/src/lib/utils/os_utils.cpp
@@ -33,8 +33,10 @@ uint32_t get_process_id()
    return ::getpid();
 #elif defined(BOTAN_TARGET_OS_IS_WINDOWS) || defined(BOTAN_TARGET_OS_IS_MINGW)
    return ::GetCurrentProcessId();
+#elif defined(BOTAN_TARGET_OS_TYPE_IS_UNIKERNEL)
+   return 0; // truly no meaningful value
 #else
-   throw Exception("get_process_id not supported");
+   #error "Missing get_process_id"
 #endif
    }
 
diff --git a/src/lib/utils/semaphore.cpp b/src/lib/utils/semaphore.cpp
index f30c43661..62c31d3e3 100644
--- a/src/lib/utils/semaphore.cpp
+++ b/src/lib/utils/semaphore.cpp
@@ -7,6 +7,8 @@
 
 #include <botan/internal/semaphore.h>
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+
 // Based on code by Pierre Gaston (http://p9as.blogspot.com/2012/06/c11-semaphores.html)
 
 namespace Botan {
@@ -15,7 +17,7 @@ void Semaphore::release(size_t n)
    {
    for(size_t i = 0; i != n; ++i)
       {
-      std::lock_guard<std::mutex> lock(m_mutex);
+      lock_guard_type<mutex_type> lock(m_mutex);
 
       ++m_value;
 
@@ -29,7 +31,7 @@ void Semaphore::release(size_t n)
 
 void Semaphore::acquire()
    {
-   std::unique_lock<std::mutex> lock(m_mutex);
+   std::unique_lock<mutex_type> lock(m_mutex);
    --m_value;
    if(m_value < 0)
       {
@@ -39,3 +41,5 @@ void Semaphore::acquire()
    }
 
 }
+
+#endif
diff --git a/src/lib/utils/semaphore.h b/src/lib/utils/semaphore.h
index 994a15f21..87e6b84fe 100644
--- a/src/lib/utils/semaphore.h
+++ b/src/lib/utils/semaphore.h
@@ -8,11 +8,15 @@
 #ifndef BOTAN_SEMAPHORE_H__
 #define BOTAN_SEMAPHORE_H__
 
-#include <mutex>
+#include <botan/mutex.h>
+
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
 #include <condition_variable>
+#endif
 
 namespace Botan {
 
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
 class Semaphore
    {
    public:
@@ -25,9 +29,10 @@ class Semaphore
    private:
       int m_value;
       int m_wakeups;
-      std::mutex m_mutex;
+      mutex_type m_mutex;
       std::condition_variable m_cond;
    };
+#endif
 
 }
 
diff --git a/src/tests/test_x509_path.cpp b/src/tests/test_x509_path.cpp
index 7e2039ab4..96cc7a190 100644
--- a/src/tests/test_x509_path.cpp
+++ b/src/tests/test_x509_path.cpp
@@ -23,7 +23,7 @@ namespace Botan_Tests {
 
 namespace {
 
-#if defined(BOTAN_HAS_X509_CERTIFICATES)
+#if defined(BOTAN_HAS_X509_CERTIFICATES) && defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
 
 std::map<std::string, std::string> read_results(const std::string& results_file)
    {
diff --git a/src/tests/unit_tls.cpp b/src/tests/unit_tls.cpp
index d52f17784..45d75dab2 100644
--- a/src/tests/unit_tls.cpp
+++ b/src/tests/unit_tls.cpp
@@ -19,7 +19,6 @@
 #include <botan/x509self.h>
 #include <botan/rsa.h>
 #include <botan/x509_ca.h>
-#include <botan/auto_rng.h>
 #include <botan/hex.h>
 #endif
 
diff --git a/src/tests/unit_tls_policy.cpp b/src/tests/unit_tls_policy.cpp
index 2e5b63f41..95290b933 100644
--- a/src/tests/unit_tls_policy.cpp
+++ b/src/tests/unit_tls_policy.cpp
@@ -10,7 +10,6 @@
 
 #if defined(BOTAN_HAS_TLS)
   #include <botan/pubkey.h>
-  #include <botan/auto_rng.h>
   #include <botan/oids.h>
   #include <botan/tls_policy.h>
 #endif