patch 8.0.0367: types in include files may be inconsistent

Problem:    If configure defines _LARGE_FILES some include files are included
            before it is defined.
Solution:   Include vim.h first. (Sam Thursfield, closes #1508)

src/gui_x11.c

@@ -12,6 +12,8 @@
  * Not used for GTK.
  */
 
+#include "vim.h"
+
 #include <X11/keysym.h>
 #include <X11/Xatom.h>
 #include <X11/StringDefs.h>
@@ -19,8 +21,6 @@
 #include <X11/Shell.h>
 #include <X11/cursorfont.h>
 
-#include "vim.h"
-
 /*
  * For Workshop XpmP.h is preferred, because it makes the signs drawn with a
  * transparent background instead of black.