[master] 50ddc2e I promise this will stop at some point

[Poul-Henning Kamp]

commit 50ddc2e9d34c45f82b7fc063f1a0f02db27a73fa
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Oct 4 10:07:12 2017 +0000

    I promise this will stop at some point

diff --git a/include/vdef.h b/include/vdef.h
index fd28a58..f52bdf8 100644
--- a/include/vdef.h
+++ b/include/vdef.h
@@ -122,11 +122,13 @@
 
 #ifdef __SUNPRO_C
 #define NEEDLESS(s)		{}
-#define __unused
 #else
 #define NEEDLESS(s)		s
 #endif
 
+#ifndef __unused
+#  define __unused
+#endif
 
 /*
  * Most of this nightmare is stolen from FreeBSD's <cdefs.h>