* dtable.cc (handle_to_fn): Check error return value from NtQueryObject first

before seeing if name buffer is NULL.
* grp.cc (read_etc_group): Fix gcc warning regarding snprintf format.
* passwd.cc (read_etc_passwd): Ditto.

winsup/cygwin/passwd.cc

@@ -177,7 +177,7 @@ read_etc_passwd ()
 		    {
 		      char strbuf[100];
 		      snprintf (linebuf, sizeof (linebuf),
-				"%s::%u:%u:%s:%s:/bin/sh",
+				"%s::%lu:%lu:%s:%s:/bin/sh",
 				cygheap->user.name (),
 				*GetSidSubAuthority(tu,
 				             *GetSidSubAuthorityCount(tu) - 1),