move -DMS2_FILTERS from CFLAGS to DEFS

configure.ac

@@ -612,10 +612,6 @@ AC_ARG_ENABLE(filters,
 	esac],
 	[filters=true])
 AM_CONDITIONAL(MS2_FILTERS, test x$filters = xtrue)
-if test "$filters" = 'true'; then
-	CFLAGS="$CFLAGS -DMS2_FILTERS"
-fi
-
 
 AM_CONDITIONAL(BUILD_VOIP_LIBRARY, test x$ortp_enabled = xtrue)
 

src/Makefile.am

@@ -267,6 +267,10 @@ AM_CXXFLAGS= $(ORTP_CFLAGS)   \
 
 DEFS=@DEFS@  -DPACKAGE_PLUGINS_DIR=\"$(PACKAGE_PLUGINS_DIR)\" -DLOCALEDIR=\"$(localedir)\" -DMS2_INTERNAL
 
+if MS2_FILTERS
+DEFS+= -DMS2_FILTERS
+endif
+
 if BUILD_VIDEO
 AM_CFLAGS+=$(VIDEO_CFLAGS) $(GLEW_CFLAGS)
 endif