Fix RPC breakage when longjumping from signal handler

	* hurd/sigunwind.c (_hurdsig_longjmp_from_handler): Destroy reply port
	of interrupted RPC instead of restoring it.

ChangeLog

@@ -1,3 +1,8 @@
+2015-11-25  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* hurd/sigunwind.c (_hurdsig_longjmp_from_handler): Destroy reply port
+	of interrupted RPC instead of restoring it.
+
 2015-11-24  Joseph Myers  <joseph@codesourcery.com>
 
 	* stdlib/strtod_nan.c: New file.

hurd/sigunwind.c

@@ -50,7 +50,8 @@ _hurdsig_longjmp_from_handler (void *data, jmp_buf env, int val)
 	  *reply_port = MACH_PORT_DEAD;
 	  __mach_port_destroy (__mach_task_self (), port);
 	}
-      *reply_port = scp->sc_reply_port;
+      if (scp->sc_reply_port)
+	__mach_port_destroy (__mach_task_self (), scp->sc_reply_port);
     }
 
   __spin_lock (&ss->lock);