Updates to a number of apps to remove warnings/compile errors under libc5.

Tested under both libc5 and libc6 and all seems well with these fixes.
 -Erik

coreutils/mkfifo.c

@@ -65,7 +65,6 @@ extern int mkfifo_main(int argc, char **argv)
 	if (mkfifo(*argv, mode) < 0) {
 		perror("mkfifo");
 		exit(255);
-	} else {
-		exit(TRUE);
 	}
+	return(TRUE);
 }