diff --git a/configure.ac b/configure.ac
index 94d719c786..4bccd32985 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1050,6 +1050,7 @@ dnl FIXME: do we want to rename to GST_ALL_* ?
 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)"
 GST_CFLAGS="-I\$(top_srcdir)/gst-libs $GST_CFLAGS $GLIB_EXTRA_CFLAGS \$(GST_OPTION_CFLAGS)"
 AC_SUBST(GST_CFLAGS)