Set -Wno-unused-but-set-variable globally

As of gcc-4.6 the option -Wunused-but-set-variable is enabled by
default.  While this is a useful warning there are numerous places
in the ZFS code when a variable is set and then only checked in an
ASSERT().  To avoid having to update every instance of this in the
code we now set -Wno-unused-but-set-variable to suppress the warning.

Additionally, when building with --enable-debug and -Werror set these
warning also become fatal.  We can reevaluate the suppression of these
error at a later time if it becomes an issue.  For now we are basically
just reverting to the previous gcc behavior.

20 files changed, 83 insertions, 62 deletions

diff --git a/cmd/mount_zfs/Makefile.in b/cmd/mount_zfs/Makefile.in
index eb30f84aa..27afbebdd 100644
--- a/cmd/mount_zfs/Makefile.in
+++ b/cmd/mount_zfs/Makefile.in
@@ -304,9 +304,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 mount_zfs_SOURCES = \
 	$(top_srcdir)/cmd/mount_zfs/mount_zfs.c
 
diff --git a/cmd/zdb/Makefile.in b/cmd/zdb/Makefile.in
index 092b6b08f..bce8a786e 100644
--- a/cmd/zdb/Makefile.in
+++ b/cmd/zdb/Makefile.in
@@ -300,9 +300,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 zdb_SOURCES = \
 	$(top_srcdir)/cmd/zdb/zdb.c \
 	$(top_srcdir)/cmd/zdb/zdb_il.c
diff --git a/cmd/zfs/Makefile.in b/cmd/zfs/Makefile.in
index f9e3c84b6..8df35a2c9 100644
--- a/cmd/zfs/Makefile.in
+++ b/cmd/zfs/Makefile.in
@@ -300,9 +300,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 zfs_SOURCES = \
 	$(top_srcdir)/cmd/zfs/zfs_iter.c \
 	$(top_srcdir)/cmd/zfs/zfs_iter.h \
diff --git a/cmd/zinject/Makefile.in b/cmd/zinject/Makefile.in
index 7f3c041da..47ee6d74a 100644
--- a/cmd/zinject/Makefile.in
+++ b/cmd/zinject/Makefile.in
@@ -300,9 +300,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 zinject_SOURCES = \
 	$(top_srcdir)/cmd/zinject/translate.c \
 	$(top_srcdir)/cmd/zinject/zinject.c \
diff --git a/cmd/zpios/Makefile.in b/cmd/zpios/Makefile.in
index 70b84e238..9f42e2d6f 100644
--- a/cmd/zpios/Makefile.in
+++ b/cmd/zpios/Makefile.in
@@ -290,9 +290,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 zpios_SOURCES = \
 	$(top_srcdir)/cmd/zpios/zpios_main.c \
 	$(top_srcdir)/cmd/zpios/zpios_util.c \
diff --git a/cmd/zpool/Makefile.in b/cmd/zpool/Makefile.in
index 39b1d3bb4..f3e4bc73e 100644
--- a/cmd/zpool/Makefile.in
+++ b/cmd/zpool/Makefile.in
@@ -301,9 +301,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 zpool_SOURCES = \
 	$(top_srcdir)/cmd/zpool/zpool_iter.c \
 	$(top_srcdir)/cmd/zpool/zpool_main.c \
diff --git a/cmd/ztest/Makefile.in b/cmd/ztest/Makefile.in
index c929bf0cc..65e36a0c9 100644
--- a/cmd/ztest/Makefile.in
+++ b/cmd/ztest/Makefile.in
@@ -300,10 +300,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 ztest_SOURCES = \
 	$(top_srcdir)/cmd/ztest/ztest.c
 
diff --git a/cmd/zvol_id/Makefile.in b/cmd/zvol_id/Makefile.in
index 7698158b0..3e8a34be0 100644
--- a/cmd/zvol_id/Makefile.in
+++ b/cmd/zvol_id/Makefile.in
@@ -290,9 +290,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 zvol_id_SOURCES = \
 	$(top_srcdir)/cmd/zvol_id/zvol_id_main.c
 
diff --git a/config/Rules.am b/config/Rules.am
index 19ee4a32c..2abafcd4d 100644
--- a/config/Rules.am
+++ b/config/Rules.am
@@ -1,7 +1,8 @@
 DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h
 
 AM_LIBTOOLFLAGS = --silent
-AM_CFLAGS  = -Wall -Wstrict-prototypes -fno-strict-aliasing ${DEBUG_CFLAGS}
+AM_CFLAGS  = -Wall -Wstrict-prototypes
+AM_CFLAGS += -fno-strict-aliasing -Wno-unused-but-set-variable ${DEBUG_CFLAGS}
 AM_CFLAGS += -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT
 AM_CFLAGS += -D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64
 AM_CFLAGS += -D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
diff --git a/config/kernel.m4 b/config/kernel.m4
index 510f6dbc7..f31d93c97 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -44,6 +44,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 
 	dnl # -Wall -fno-strict-aliasing -Wstrict-prototypes and other
 	dnl # compiler options are added by the kernel build system.
+	KERNELCPPFLAGS="$KERNELCPPFLAGS -Wno-unused-but-set-variable"
 	KERNELCPPFLAGS="$KERNELCPPFLAGS -DHAVE_SPL -D_KERNEL"
 	KERNELCPPFLAGS="$KERNELCPPFLAGS -DTEXT_DOMAIN=\\\"zfs-linux-kernel\\\""
 
diff --git a/configure b/configure
index feffaae48..30f3b325c 100755
--- a/configure
+++ b/configure
@@ -14364,7 +14364,8 @@ _ACEOF
 
 
 
-			KERNELCPPFLAGS="$KERNELCPPFLAGS -DHAVE_SPL -D_KERNEL"
+			KERNELCPPFLAGS="$KERNELCPPFLAGS -Wno-unused-but-set-variable"
+	KERNELCPPFLAGS="$KERNELCPPFLAGS -DHAVE_SPL -D_KERNEL"
 	KERNELCPPFLAGS="$KERNELCPPFLAGS -DTEXT_DOMAIN=\\\"zfs-linux-kernel\\\""
 
 
@@ -18409,7 +18410,8 @@ _ACEOF
 
 
 
-			KERNELCPPFLAGS="$KERNELCPPFLAGS -DHAVE_SPL -D_KERNEL"
+			KERNELCPPFLAGS="$KERNELCPPFLAGS -Wno-unused-but-set-variable"
+	KERNELCPPFLAGS="$KERNELCPPFLAGS -DHAVE_SPL -D_KERNEL"
 	KERNELCPPFLAGS="$KERNELCPPFLAGS -DTEXT_DOMAIN=\\\"zfs-linux-kernel\\\""
 
 
diff --git a/lib/libavl/Makefile.in b/lib/libavl/Makefile.in
index 29441be7e..863d72e30 100644
--- a/lib/libavl/Makefile.in
+++ b/lib/libavl/Makefile.in
@@ -310,10 +310,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 lib_LTLIBRARIES = libavl.la
 libavl_la_SOURCES = \
 	$(top_srcdir)/module/avl/avl.c
diff --git a/lib/libefi/Makefile.in b/lib/libefi/Makefile.in
index 9f918294c..77f99b6b5 100644
--- a/lib/libefi/Makefile.in
+++ b/lib/libefi/Makefile.in
@@ -310,10 +310,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 lib_LTLIBRARIES = libefi.la
 libefi_la_SOURCES = \
 	$(top_srcdir)/lib/libefi/rdwr_efi.c
diff --git a/lib/libnvpair/Makefile.in b/lib/libnvpair/Makefile.in
index 0848c9427..31a6ccba7 100644
--- a/lib/libnvpair/Makefile.in
+++ b/lib/libnvpair/Makefile.in
@@ -311,10 +311,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 lib_LTLIBRARIES = libnvpair.la
 libnvpair_la_SOURCES = \
 	$(top_srcdir)/lib/libnvpair/libnvpair.c \
diff --git a/lib/libspl/Makefile.in b/lib/libspl/Makefile.in
index 7e1bc6d5a..e9f98817a 100644
--- a/lib/libspl/Makefile.in
+++ b/lib/libspl/Makefile.in
@@ -361,10 +361,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 SUBDIRS = include $(TARGET_ASM_DIR)
 DIST_SUBDIRS = include asm-generic asm-i386 asm-x86_64
 AM_CCASFLAGS = \
diff --git a/lib/libspl/asm-generic/Makefile.in b/lib/libspl/asm-generic/Makefile.in
index b49f38c4f..22f975042 100644
--- a/lib/libspl/asm-generic/Makefile.in
+++ b/lib/libspl/asm-generic/Makefile.in
@@ -259,9 +259,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 atomic_SOURCE = atomic.c
 atomic_ASM = atomic.S
 COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) \
diff --git a/lib/libunicode/Makefile.in b/lib/libunicode/Makefile.in
index 617f30817..6098ce959 100644
--- a/lib/libunicode/Makefile.in
+++ b/lib/libunicode/Makefile.in
@@ -310,10 +310,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 lib_LTLIBRARIES = libunicode.la
 libunicode_la_SOURCES = \
 	$(top_srcdir)/module/unicode/u8_textprep.c \
diff --git a/lib/libuutil/Makefile.in b/lib/libuutil/Makefile.in
index 168724d80..c20081946 100644
--- a/lib/libuutil/Makefile.in
+++ b/lib/libuutil/Makefile.in
@@ -312,10 +312,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 lib_LTLIBRARIES = libuutil.la
 libuutil_la_LIBADD = $(top_builddir)/lib/libavl/libavl.la
 libuutil_la_SOURCES = \
diff --git a/lib/libzfs/Makefile.in b/lib/libzfs/Makefile.in
index 2880412ab..bcd310151 100644
--- a/lib/libzfs/Makefile.in
+++ b/lib/libzfs/Makefile.in
@@ -320,9 +320,10 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\"
 lib_LTLIBRARIES = libzfs.la
 libzfs_la_LDFLAGS = -lm -ldl $(LIBSELINUX)
 libzfs_la_LIBADD = \
diff --git a/lib/libzpool/Makefile.in b/lib/libzpool/Makefile.in
index 39feb9d27..56b449365 100644
--- a/lib/libzpool/Makefile.in
+++ b/lib/libzpool/Makefile.in
@@ -331,10 +331,11 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h \
 	-I$(top_srcdir)/include -I$(top_srcdir)/lib/libspl/include
 AM_LIBTOOLFLAGS = --silent
 AM_CFLAGS = -Wall -Wstrict-prototypes -fno-strict-aliasing \
-	${DEBUG_CFLAGS} -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT \
-	-D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 \
-	-D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" \
-	$(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+	-Wno-unused-but-set-variable ${DEBUG_CFLAGS} -D_GNU_SOURCE \
+	-D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS \
+	-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE \
+	-DTEXT_DOMAIN=\"zfs-linux-user\" $(DEBUG_STACKFLAGS) \
+	$(FRAME_LARGER_THAN)
 lib_LTLIBRARIES = libzpool.la
 libzpool_la_LIBADD = \
 	$(top_builddir)/lib/libunicode/libunicode.la \