Only <glib.h> can be included directly.
--- librr/rr-debug.h.orig	2002-11-28 15:00:24.000000000 -0600
+++ librr/rr-debug.h	2020-01-28 04:41:29.000000000 -0600
@@ -14,7 +14,7 @@
 #ifndef __RR_DEBUG_H__
 #define __RR_DEBUG_H__
 
-#include <glib/gmessages.h>
+#include <glib.h>
 
 typedef enum                                                                                 
 {