6 files changed, 14 insertions, 6 deletions
diff --git a/src/lib/entropy/egd/es_egd.h b/src/lib/entropy/egd/es_egd.h
index 5afdc5a41..3f46bc64f 100644
--- a/src/lib/entropy/egd/es_egd.h
+++ b/src/lib/entropy/egd/es_egd.h
@@ -11,6 +11,7 @@
 #include <botan/entropy_src.h>
 #include <string>
 #include <vector>
+#include <mutex>
 
 namespace Botan {
 
diff --git a/src/lib/entropy/unix_procs/unix_procs.h b/src/lib/entropy/unix_procs/unix_procs.h
index 00ebe13ad..b2505fcd5 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 <sys/types.h>
+#include <mutex>
 
 namespace Botan {
 
diff --git a/src/lib/modes/aead/aead.h b/src/lib/modes/aead/aead.h
index 41fc605ba..6bbb39dcb 100644
--- a/src/lib/modes/aead/aead.h
+++ b/src/lib/modes/aead/aead.h
@@ -55,11 +55,6 @@ class BOTAN_DLL AEAD_Mode : public Cipher_Mode
       * modes, and large enough that random collisions are unlikely).
       */
       size_t default_nonce_length() const override { return 12; }
-
-      /**
-      * Return the size of the authentication tag used (in bytes)
-      */
-      virtual size_t tag_size() const = 0;
    };
 
 /**
diff --git a/src/lib/modes/cipher_mode.h b/src/lib/modes/cipher_mode.h
index 110053489..63821005d 100644
--- a/src/lib/modes/cipher_mode.h
+++ b/src/lib/modes/cipher_mode.h
@@ -24,6 +24,11 @@ class BOTAN_DLL Cipher_Mode : public Keyed_Transform
       * confidentiality.
       */
       virtual bool authenticated() const { return false; }
+
+      /**
+      * Return the size of the authentication tag used (in bytes)
+      */
+      virtual size_t tag_size() const { return 0; }
    };
 
 /**
diff --git a/src/lib/utils/version.cpp b/src/lib/utils/version.cpp
index d13d091ca..f3e01e290 100644
--- a/src/lib/utils/version.cpp
+++ b/src/lib/utils/version.cpp
@@ -21,6 +21,11 @@ namespace Botan {
 */
 std::string version_string()
    {
+   return std::string(version_cstr());
+   }
+
+const char* version_cstr()
+   {
 #define QUOTE(name) #name
 #define STR(macro) QUOTE(macro)
 
diff --git a/src/lib/utils/version.h b/src/lib/utils/version.h
index c2f070433..3fc6f5fe7 100644
--- a/src/lib/utils/version.h
+++ b/src/lib/utils/version.h
@@ -24,6 +24,8 @@ namespace Botan {
 */
 BOTAN_DLL std::string version_string();
 
+BOTAN_DLL const char* version_cstr();
+
 /**
 * Return the date this version of botan was released, in an integer of
 * the form YYYYMMDD. For instance a version released on May 21, 2013