Cygwin: getgrent: fix local SAM enumeration on domain member machines

Don't skip output of local SAM groups on domain member machines.
They can have valid, user-defined groups in their SAM.  Just
skip builtin groups if we're enumerating AD as well.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/grp.cc

@@ -424,9 +424,15 @@ gr_ent::enumerate_local ()
 	  DWORD dlen = DNLEN + 1;
 	  SID_NAME_USE acc_type;
 
-	  LookupAccountNameW (NULL,
+	  if (!LookupAccountNameW (NULL,
 				 ((PLOCALGROUP_INFO_0) buf)[cnt++].lgrpi0_name,
-			      sid, &slen, dom, &dlen, &acc_type);
+				 sid, &slen, dom, &dlen, &acc_type))
+	    continue;
+	  if (sid_id_auth (sid) == 5 /* SECURITY_NT_AUTHORITY */
+	      && sid_sub_auth (sid, 0) == SECURITY_BUILTIN_DOMAIN_RID
+	      && cygheap->dom.member_machine ()
+	      && nss_db_enum_primary ())
+	    continue;
 	  fetch_user_arg_t arg;
 	  arg.type = SID_arg;
 	  arg.sid = &sid;

winsup/cygwin/passwd.cc

@@ -385,8 +385,6 @@ pg_ent::getent (void)
     case from_local:
       if (from_db
 	  && nss_db_enum_local ()
-	  && (!cygheap->dom.member_machine ()
-	      || !nss_db_enum_primary ())
 	  && (entry = enumerate_local ()))
 	return entry;
       state = from_sam;