Fixed header dependencies to be fully compatible with the Windows
headers (with help from Dimitrie O. Paun).

dlls/shell32/classes.c

diff --git a/dlls/shell32/classes.c b/dlls/shell32/classes.c
index 64b00a3..0ac39b1 100644
--- a/dlls/shell32/classes.c
+++ b/dlls/shell32/classes.c
@@ -24,10 +24,15 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include "wine/debug.h"
 #include "winerror.h"
+#include "windef.h"
+#include "winbase.h"
 #include "winreg.h"
+#include "wingdi.h"
+#include "winuser.h"
 
 #include "shlobj.h"
 #include "shell32_main.h"