diff --git a/gtk/gtkmain.c b/gtk/gtkmain.c
index 9e2a6df548..20e2cea1ec 100644
--- a/gtk/gtkmain.c
+++ b/gtk/gtkmain.c
@@ -361,11 +361,6 @@ check_setugid (void)
   gid_t rgid, egid, sgid; /* Real, effective and saved group ID's */
   
 #ifdef HAVE_GETRESUID
-  /* These aren't in the header files, so we prototype them here.
-   */
-  int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
-  int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);
-
   if (getresuid (&ruid, &euid, &suid) != 0 ||
       getresgid (&rgid, &egid, &sgid) != 0)
 #endif /* HAVE_GETRESUID */