Set close-on-exec flag on server socket.

diff --git a/scheduler/client.c b/scheduler/client.c
index c2e7dac..9f22739 100644
--- a/scheduler/client.c
+++ b/scheduler/client.c
@@ -284,6 +284,7 @@
         exit(1);
     case 0:  /* child */
         close( fd[1] );
+        fcntl( fd[0], F_SETFD, 1 ); /* set close on exec flag */
         break;
     default:  /* parent */
         close( fd[0] );