From 2dd7d0560aad8e717f15329e1814f654fe10547c Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Sat, 13 Feb 2016 17:23:55 +0000
Subject: [PATCH] Hide ucontext_t and mcontext_t when neither POSIX nor XSI
 features are enabled in the compilation environment, i.e. for ANSI C use of
 #include <signal.h>.

Requested and reviewed by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	13 days
---
 include/signal.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/signal.h b/include/signal.h
index 33be55c6dd25..217faddea03d 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -36,8 +36,10 @@
 #include <sys/cdefs.h>
 #include <sys/_types.h>
 #include <sys/signal.h>
+#if __POSIX_VISIBLE >= 200112 || __XSI_VISIBLE
 #include <machine/ucontext.h>
 #include <sys/_ucontext.h>
+#endif
 
 #if __BSD_VISIBLE
 /*