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

diff --git a/include/wingdi.h b/include/wingdi.h
index e60203a..db191ed 100644
--- a/include/wingdi.h
+++ b/include/wingdi.h
@@ -1688,7 +1688,7 @@
   BYTE rgbtRed;
 } RGBTRIPLE;
 
-#include "pshpack2.h"
+#include <pshpack2.h>
 typedef struct
 {
     WORD    bfType;
@@ -1697,7 +1697,7 @@
     WORD    bfReserved2;
     DWORD   bfOffBits;
 } BITMAPFILEHEADER, *PBITMAPFILEHEADER, *LPBITMAPFILEHEADER;
-#include "poppack.h"
+#include <poppack.h>
 
 #define MAKEPOINTS(l)  (*((POINTS *)&(l)))
 
@@ -1835,7 +1835,7 @@
 
 #define CLR_INVALID         0xffffffff
 /* Metafile header structure */
-#include "pshpack2.h"
+#include <pshpack2.h>
 typedef struct
 {
     WORD       mtType;
@@ -1846,7 +1846,7 @@
     DWORD      mtMaxRecord;
     WORD       mtNoParameters;
 } METAHEADER, *PMETAHEADER, *LPMETAHEADER;
-#include "poppack.h"
+#include <poppack.h>
 
 /* Metafile typical record structure */
 typedef struct