Use a GCC-specific #pragma instead of GCC-specific

-Wno-uninitialized to silence a bogus warning.

configure.ac

@@ -534,8 +534,6 @@ lc_CPUCORES
 # If using GCC, set some additional AM_CFLAGS:
 ###############################################################################
 
-Wno_uninitialized=no
-
 if test "x$GCC" = xyes ; then
 	echo
 	echo "GCC extensions:"
@@ -544,15 +542,6 @@ if test "x$GCC" = xyes ; then
 		AM_CFLAGS="$AM_CFLAGS $CFLAG_VISIBILITY"
 	fi
 
-	# -Wno-uninitialized is needed with -Werror with SHA256 code
-	# to omit a bogus warning.
-	AC_MSG_CHECKING([if $CC accepts -Wno-uninitialized])
-	OLD_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS -Wno-uninitialized"
-	AC_COMPILE_IFELSE([void foo(void) { }], [Wno_uninitialized=yes])
-	CFLAGS="$OLD_CFLAGS"
-	AC_MSG_RESULT([$Wno_uninitialized])
-
 	# Enable as much warnings as possible. These commented warnings won't
 	# work for this package though:
 	#   * -Wunreachable-code breaks several assert(0) cases, which are
@@ -608,8 +597,6 @@ if test "x$GCC" = xyes ; then
 	fi
 fi
 
-AM_CONDITIONAL([COND_WNO_UNINITIALIZED], test "x$Wno_uninitialized" = "xyes")
-
 
 ###############################################################################
 # Create the makefiles and config.h

src/liblzma/check/Makefile.am

@@ -44,9 +44,4 @@ endif
 
 if COND_CHECK_SHA256
 libcheck_la_SOURCES += sha256.c
-# Hide bogus warning to allow usage of -Werror. If more issues like this
-# pop up, we'll drop -Werror.
-if COND_WNO_UNINITIALIZED
-AM_CFLAGS += -Wno-uninitialized
-endif
 endif

src/liblzma/check/sha256.c

@@ -22,6 +22,11 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
+// Avoid bogus warnings in transform().
+#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 2) || __GNUC__ > 4
+#	pragma GCC diagnostic ignored "-Wuninitialized"
+#endif
+
 #include "check.h"
 
 #ifndef WORDS_BIGENDIAN