* src/chfn.c, src/chsh.c, src/expiry.c, src/gpasswd.c,

src/newgrp.c, src/passwd.c, src/su.c: Use the same stderr and
	syslog warnings when the username cannot be determined.
	* src/newgrp.c: Reuse the same stderr message for groups which do
	not exist in the system.

src/su.c

@@ -468,7 +468,10 @@ int main (int argc, char **argv)
 	 */
 	pw = get_my_pwent ();
 	if (NULL == pw) {
-		SYSLOG ((LOG_CRIT, "Unknown UID: %u", my_uid));
+		fprintf (stderr, _("%s: Cannot determine your user name.\n"),
+		         Prog);
+		SYSLOG ((LOG_WARN, "Cannot determine the user name of the caller (UID %lu)",
+		         (unsigned long) my_uid));
 		su_failure (tty);
 	}
 	STRFCPY (oldname, pw->pw_name);