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/whoami.c

@@ -45,5 +45,5 @@ extern int whoami_main(int argc, char **argv)
 	}
 	fprintf(stderr, "%s: cannot find username for UID %u\n", argv[0],
 			(unsigned) uid);
-	exit(FALSE);
+	return(FALSE);
 }