Import <stdnoreturn.h>

This header conforms to the C11 standard
Reference: ISO/IEC 9899:201x 7.23 _Noreturn <stdnoreturn.h>

According to ISO/IEC 9899:201x (draft) <stdnoreturn.> defines the
noreturn macro which expands to _Noreturn.

The _Noreturn keyword appears in a function declaration and specifies
that the function does not return by reaching the end of the function
body.

Design choices:
 - don't implicitly break C++ code including this header with #error
   C++11 offers [[noreturn]] which conflicts with C11 _Noreturn

 - don't check for __STDC_VERSION__, everybody is free to reuse it with
   a nonstandard compiler not conforming to C11 but supporting _Noreturn

   gcc(1) and clang(1) support _Noreturn in -std=c99 and older standards

   this follows <stdbool.h> choice for not checking for C99

 - follow <stdbool.h> and declare the __noreturn_is_defined guard

 - use a standard header guard (_STDNORETURN_H_), similar to <stdbool.h>

Reviewed by <pgoyette> and <joerg>

distrib/sets/lists/comp/mi

@@ -1,4 +1,4 @@
-#	$NetBSD: mi,v 1.2060 2016/09/05 02:25:37 ozaki-r Exp $
+#	$NetBSD: mi,v 1.2061 2016/10/02 13:09:24 kamil Exp $
 #
 # Note: don't delete entries from here - mark them as "obsolete" instead.
 ./etc/mtree/set.comp				comp-sys-root
@@ -2745,6 +2745,7 @@
 ./usr/include/stdint.h				comp-c-include
 ./usr/include/stdio.h				comp-c-include
 ./usr/include/stdlib.h				comp-c-include
+./usr/include/stdnoreturn.h			comp-c-include
 ./usr/include/string.h				comp-c-include
 ./usr/include/stringlist.h			comp-c-include
 ./usr/include/strings.h				comp-c-include

include/Makefile

@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile,v 1.141 2015/07/29 00:10:26 christos Exp $
+#	$NetBSD: Makefile,v 1.142 2016/10/02 13:09:24 kamil Exp $
 #	@(#)Makefile	8.2 (Berkeley) 1/4/94
 
 # Doing a make includes builds /usr/include
@@ -19,9 +19,10 @@ INCS=	a.out.h aio.h ar.h assert.h atomic.h \
 	paths.h pwd.h quota.h randomid.h ranlib.h re_comp.h regex.h regexp.h \
 	resolv.h res_update.h rmt.h sched.h search.h semaphore.h setjmp.h \
 	string.h sgtty.h signal.h spawn.h stab.h stddef.h stdio.h \
-	stdlib.h strings.h stringlist.h struct.h sysexits.h tar.h time.h \
-	ttyent.h tzfile.h ucontext.h ulimit.h unistd.h util.h utime.h utmp.h \
-	utmpx.h uuid.h vis.h wchar.h wctype.h wordexp.h
+	stdlib.h stdnoreturn.h strings.h stringlist.h struct.h sysexits.h \
+	tar.h time.h ttyent.h tzfile.h \
+	ucontext.h ulimit.h unistd.h util.h utime.h utmp.h utmpx.h uuid.h \
+	vis.h wchar.h wctype.h wordexp.h
 INCS+=	arpa/ftp.h arpa/inet.h arpa/nameser.h arpa/nameser_compat.h \
 	arpa/telnet.h arpa/tftp.h
 INCS+=	protocols/dumprestore.h protocols/routed.h protocols/rwhod.h \

include/stdnoreturn.h

@@ -0,0 +1,42 @@
+/*	$NetBSD: stdnoreturn.h,v 1.1 2016/10/02 13:09:24 kamil Exp $	*/
+
+/*-
+ * Copyright (c) 2016 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Kamil Rytarowski.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _STDNORETURN_H_
+#define _STDNORETURN_H_
+
+/* ISO/IEC 9899:201x 7.23 _Noreturn <stdnoreturn.h> */
+
+#ifndef __noreturn_is_defined
+#define noreturn	_Noreturn
+#define __noreturn_is_defined
+#endif /* __noreturn_is_defined */
+
+#endif