diff --git a/configure.ac b/configure.ac
index 9240fb1614177aa6d665867f7bd23036e8c35833..935e851740e6850ccd36a5c2576976f98cd310dd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2237,7 +2237,7 @@ AS_IF([test "${enable_sid}" != "no"], [
         CPPFLAGS="$CPPFLAGS $SID_CFLAGS"
         AC_CHECK_HEADER([sidplay/builders/resid.h], [
             VLC_ADD_PLUGIN([sid])
-            VLC_ADD_CFLAGS([sid], [$SID_CFLAGS])
+            VLC_ADD_CXXFLAGS([sid], [$SID_CFLAGS])
             VLC_ADD_LIBS([sid], [$SID_LIBS] [-lresid-builder])
         ], [
             AS_IF([test -n "${enable_sid}"],
diff --git a/modules/demux/Makefile.am b/modules/demux/Makefile.am
index 86dfd8abeeda325baacaf67551707a5833c9f21f..802ce9038b2d8dc06d368481e538d736c0e24feb 100644
--- a/modules/demux/Makefile.am
+++ b/modules/demux/Makefile.am
@@ -119,7 +119,7 @@ EXTRA_LTLIBRARIES += libgme_plugin.la
 demux_LTLIBRARIES += $(LTLIBgme)
 
 libsid_plugin_la_SOURCES = demux/sid.cpp
-libsid_plugin_la_CFLAGS = $(AM_CFLAGS) $(CFLAGS_sid)
+libsid_plugin_la_CXXFLAGS = $(AM_CXXFLAGS) $(CXXFLAGS_sid)
 libsid_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(demuxdir)'
 libsid_plugin_la_LIBADD = $(LIBS_sid)
 EXTRA_LTLIBRARIES += libsid_plugin.la