(main): Don't catch SIGPIPE if no such signal.

From-SVN: r5782

gcc/cccp.c

@@ -1030,7 +1030,9 @@ main (argc, argv)
   }
 #endif /* RLIMIT_STACK defined */
 
+#ifdef SIGPIPE
   signal (SIGPIPE, pipe_closed);
+#endif
 
   p = argv[0] + strlen (argv[0]);
   while (p != argv[0] && p[-1] != '/') --p;