girepository: Ensure config.h is included first in gdump.c

Follow on from the previous commit.

Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>

Helps: #3155

girepository/gdump.c

@@ -21,10 +21,6 @@
  * Boston, MA 02111-1307, USA.
  */
 
-#include <glib.h>
-#include <glib-object.h>
-#include <gio/gio.h>
-
 /* This file is both compiled into libgirepository.so, and installed
  * on the filesystem.  But for the dumper, we want to avoid linking
  * to libgirepository; see
@@ -35,6 +31,10 @@
 #include "girepository.h"
 #endif
 
+#include <glib.h>
+#include <glib-object.h>
+#include <gio/gio.h>
+
 #include <stdlib.h>
 #include <string.h>