isystem: ship and use stdarg.h

Ship minimal stdarg.h (1 type, 4 macros) as <linux/stdarg.h>.
stdarg.h is the only userspace header commonly used in the kernel.

GPL 2 version of <stdarg.h> can be extracted from
http://archive.debian.org/debian/pool/main/g/gcc-4.2/gcc-4.2_4.2.4.orig.tar.gz

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/fs/reiserfs/prints.c b/fs/reiserfs/prints.c
index 500f200..30319dc 100644
--- a/fs/reiserfs/prints.c
+++ b/fs/reiserfs/prints.c
@@ -8,7 +8,7 @@
 #include <linux/string.h>
 #include <linux/buffer_head.h>
 
-#include <stdarg.h>
+#include <linux/stdarg.h>
 
 static char error_buf[1024];
 static char fmt_buf[1024];