configure.in: define __STDC_WANT_LIB_EXT1__

* configure.in (__STDC_WANT_LIB_EXT1__): necessary to use memset_s
  in strict C99 mode.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53252 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Wed Dec 23 02:59:26 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (__STDC_WANT_LIB_EXT1__): necessary to use memset_s
+	  in strict C99 mode.
+
 Wed Dec 23 02:34:36 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* regexec.c (match_at): move direct threaded VM code to get rid of

configure.in

@@ -2317,6 +2317,8 @@ AC_CHECK_FUNCS(utimes)
 AC_CHECK_FUNCS(wait4)
 AC_CHECK_FUNCS(waitpid)
 
+AS_IF([test "$ac_cv_func_memset_s" = yes], [AC_DEFINE([__STDC_WANT_LIB_EXT1__], 1)])
+
 AS_IF([test "$ac_cv_func_getcwd" = yes], [
     AC_CACHE_CHECK(if getcwd allocates buffer if NULL is given, [rb_cv_getcwd_malloc],
 	[AC_TRY_RUN([