diff --git a/docs/libs/Makefile.am b/docs/libs/Makefile.am
index aaa35658d7..cd3438778f 100644
--- a/docs/libs/Makefile.am
+++ b/docs/libs/Makefile.am
@@ -49,7 +49,7 @@ extra_files =
 
 # CFLAGS and LDFLAGS for compiling scan program. Only needed if your app/lib
 # contains GtkObjects/GObjects and you want to document signals and properties.
-GTKDOC_CFLAGS = $(GST_PLUGINS_BAD_CFLAGS) $(GST_BAD_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS)
+GTKDOC_CFLAGS = -DGST_USE_UNSTABLE_API $(GST_PLUGINS_BAD_CFLAGS) $(GST_BAD_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS)
 GTKDOC_LIBS = \
 	$(top_builddir)/gst-libs/gst/codecparsers/libgstcodecparsers-@GST_MAJORMINOR@.la \
 	$(top_builddir)/gst-libs/gst/basecamerabinsrc/libgstbasecamerabinsrc-@GST_MAJORMINOR@.la \