Include glib.h instead of an internal header.

--- a/goffice-bits/goffice/app/goffice-app.h	2007-01-17 00:17:27.000000000 +0100
+++ b/goffice-bits/goffice/app/goffice-app.h	2014-09-05 19:02:59.402064713 +0200
@@ -22,7 +22,7 @@
 #ifndef GOFFICE_APP_H
 #define GOFFICE_APP_H
 
-#include <glib/gmacros.h>
+#include <glib.h>
 
 G_BEGIN_DECLS
 
