Fix build error when compiling with mingw

uintptr_t must be defined when including valgrind.h, just move it as
last include solves the problem.

https://bugzilla.gnome.org/show_bug.cgi?id=796283

gobject/gclosure.c

@@ -22,7 +22,6 @@
 
 #include "config.h"
 
-#include "../glib/valgrind.h"
 #include <string.h>
 
 #include <ffi.h>
@@ -35,6 +34,7 @@
 #include "gvaluetypes.h"
 #include "gtype-private.h"
 
+#include "../glib/valgrind.h"
 
 /**
  * SECTION:gclosure

gobject/gtype.c

@@ -21,7 +21,6 @@
 
 #include "config.h"
 
-#include "../glib/valgrind.h"
 #include <string.h>
 
 #include "gtype.h"
@@ -38,6 +37,8 @@
 #include <windows.h>
 #endif
 
+#include "../glib/valgrind.h"
+
 #ifdef	G_ENABLE_DEBUG
 #define	IF_DEBUG(debug_type)	if (_g_type_debug_flags & G_TYPE_DEBUG_ ## debug_type)
 #endif