diff --git a/tests/examples/gtk/glliveshader.c b/tests/examples/gtk/glliveshader.c
index d8c8d35063..5a71bc3fcb 100644
--- a/tests/examples/gtk/glliveshader.c
+++ b/tests/examples/gtk/glliveshader.c
@@ -25,6 +25,10 @@
 #include <X11/Xlib.h>
 #endif
 
+#ifndef GL_GEOMETRY_SHADER
+#define GL_GEOMETRY_SHADER 0x8DD9
+#endif
+
 static GMainLoop *loop;
 
 static const gchar *vert = "#version 330\n\