Use angle brackets (<>) rather than quotes ("") for the include
directives in our .h files. This should avoid some potentially nasty
surprises for Winelib apps.

include/winuser.h

diff --git a/include/winuser.h b/include/winuser.h
index 9d449ec..df82e0a 100644
--- a/include/winuser.h
+++ b/include/winuser.h
@@ -2412,7 +2412,7 @@
 
 typedef BOOL  (CALLBACK *MONITORENUMPROC)(HMONITOR,HDC,LPRECT,LPARAM);
 
-#include "pshpack2.h"
+#include <pshpack2.h>
 
 typedef struct tagDLGTEMPLATE
 {
@@ -2450,7 +2450,7 @@
 typedef DLGITEMTEMPLATE *LPDLGITEMTEMPLATEW;
 DECL_WINELIB_TYPE_AW(LPDLGITEMTEMPLATE)
 
-#include "poppack.h"
+#include <poppack.h>
 
   /* CBT hook values */
 #define HCBT_MOVESIZE	    0