signal.c: return proper member

* signal.c (ruby_signal): should return either `old.sa_sigaction`
  or `old.sa_handler`, depending on whether `SA_SIGINFO` is set in
  `old.sa_flags`, because they may not be a union.
  [ruby-core:62836] [Bug #9878]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46233 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Thu May 29 23:27:50 2014  Rei Odaira  <Rei.Odaira@gmail.com>
+
+	* signal.c (ruby_signal): should return either `old.sa_sigaction`
+	  or `old.sa_handler`, depending on whether `SA_SIGINFO` is set in
+	  `old.sa_flags`, because they may not be a union.
+	  [ruby-core:62836] [Bug #9878]
+
 Thu May 29 23:11:20 2014  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (pipe_open): Close pipes when rb_execarg_fixup() raises

signal.c

@@ -595,7 +595,10 @@ ruby_signal(int signum, sighandler_t handler)
 	    rb_bug_errno("sigaction", errno);
 	}
     }
-    return old.sa_handler;
+    if (old.sa_flags & SA_SIGINFO)
+	return (sighandler_t)old.sa_sigaction;
+    else
+	return old.sa_handler;
 }
 
 sighandler_t