autotools: use -fno-strict-aliasing where supported

https://bugzilla.gnome.org/show_bug.cgi?id=769183

configure.ac

@@ -974,6 +974,10 @@ if test "x$HAVE_CXX" = "xyes"; then
 fi
 AC_SUBST(VISIBILITY_CXXFLAGS)
 
+dnl disable strict aliasing
+AS_COMPILER_FLAG([-fno-strict-aliasing], [EXTRA_CFLAGS="-fno-strict-aliasing"])
+AC_SUBST(EXTRA_CFLAGS)
+
 dnl every flag in GST_OPTION_CFLAGS, GST_OPTION_CXXFLAGS and GST_OPTION_OBJCFLAGS can be overridden
 dnl at make time with e.g. make ERROR_CFLAGS=""
 GST_OPTION_CFLAGS="\$(WARNING_CFLAGS) \$(ERROR_CFLAGS) \$(DEBUG_CFLAGS) \$(PROFILE_CFLAGS) \$(GCOV_CFLAGS) \$(OPT_CFLAGS) \$(DEPRECATED_CFLAGS)"
@@ -991,9 +995,9 @@ dnl prefer internal headers to already installed ones
 dnl also add builddir include for enumtypes and marshal
 dnl add ERROR_CFLAGS, but overridable
 GST_CFLAGS="$GST_CFLAGS -DGST_USE_UNSTABLE_API"
-GST_CXXFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_CXXFLAGS) \$(VISIBILITY_CXXFLAGS)"
-GST_OBJCFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_OBJCFLAGS)"
-GST_CFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_CFLAGS) \$(VISIBILITY_CFLAGS)"
+GST_CXXFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $EXTRA_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_CXXFLAGS) \$(VISIBILITY_CXXFLAGS)"
+GST_OBJCFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $EXTRA_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_OBJCFLAGS)"
+GST_CFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $EXTRA_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_CFLAGS) \$(VISIBILITY_CFLAGS)"
 AC_SUBST(GST_CFLAGS)
 AC_SUBST(GST_CXXFLAGS)
 AC_SUBST(GST_OBJCFLAGS)

tests/check/Makefile.am

@@ -435,7 +435,7 @@ noinst_LTLIBRARIES = libparser.la
 libparser_la_SOURCES = elements/parser.c elements/parser.h
 libparser_la_CFLAGS = \
 	-I$(top_srcdir)/tests/check \
-	$(GST_CHECK_CFLAGS) $(GST_OPTION_CFLAGS) -DGST_USE_UNSTABLE_API
+	$(AM_CFLAGS) -DGST_USE_UNSTABLE_API
 
 elements_aacparse_LDADD = libparser.la $(LDADD)