$NetBSD: patch-ae,v 1.2 2012/01/05 12:02:38 cegger Exp $

--- xen/include/xen/stdarg.h.orig	2012-01-05 11:29:11.000000000 +0000
+++ xen/include/xen/stdarg.h
@@ -1,5 +1,26 @@
+#ifndef __XEN_STDARG_H__
+#define __XEN_STDARG_H__
+
 #if defined(__OpenBSD__)
 #  include "/usr/include/stdarg.h"
+#elif defined (__NetBSD__)
+   /* Why not just include stdarg.h like everyone else? should explain */
+   typedef __builtin_va_list va_list;
+#  ifdef __GNUC__
+#    define __GNUC_PREREQ__(x, y)                                           \
+        ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||                  \
+         (__GNUC__ > (x)))
+#  else
+#    define __GNUC_PREREQ__(x, y)   0
+#  endif
+#  if !__GNUC_PREREQ__(4, 5)
+#    define __builtin_va_start(ap, last)    __builtin_stdarg_start((ap), (last))
+#  endif
+#  define va_start(ap, last)    __builtin_va_start((ap), (last))
+#  define va_end(ap)            __builtin_va_end(ap)
+#  define va_arg                __builtin_va_arg
 #else
 #  include <stdarg.h>
 #endif
+
+#endif /* __XEN_STDARG_H__ */