Deal with _POSIX_SAVED_IDS when relinquishing privileges

$OpenBSD: patch-unix_spawn_c,v 1.1.1.1 2001/07/13 02:27:16 fgsch Exp $
--- unix/spawn.c.orig	Sun Aug 20 15:30:41 1995
+++ unix/spawn.c	Thu Jul 12 21:56:10 2001
@@ -353,8 +353,10 @@ ixsspawn (pazargs, aidescs, fkeepuid, fk
   if (! fkeepuid)
     {
       /* Return to the uid of the invoking user.  */
-      (void) setuid (getuid ());
+      (void) setegid (getgid ());
       (void) setgid (getgid ());
+      (void) seteuid (getuid ());
+      (void) setuid (getuid ());
     }
   else
     {