diff -ru xscreensaver-5.05.orig/driver/prefs.c xscreensaver-5.05/driver/prefs.c
--- xscreensaver-5.05.orig/driver/prefs.c	2006-05-24 00:03:47 +0200
+++ xscreensaver-5.05/driver/prefs.c	2008-03-11 09:20:58 +0100
@@ -951,9 +951,12 @@
 	{
 	  p->init_file_date = write_date;
 
+/* Interix has no sync() or alike. */
+#ifndef __INTERIX
 	  /* Since the .xscreensaver file is used for IPC, let's try and make
 	     sure that the bits actually land on the disk right away. */
 	  sync ();
+#endif
 
           status = 0;    /* wrote and renamed successfully! */
 	}
diff -ru xscreensaver-5.05.orig/driver/setuid.c xscreensaver-5.05/driver/setuid.c
--- xscreensaver-5.05.orig/driver/setuid.c	2006-02-09 03:33:29 +0100
+++ xscreensaver-5.05/driver/setuid.c	2008-03-11 09:22:59 +0100
@@ -136,9 +136,12 @@
   if (uid == (uid_t) -1) uid = (uid_t) -2;
 
   errno = 0;
+
+#ifndef __INTERIX
   if (setgroups_needed_p (gid) &&
       setgroups (1, &gid) < 0)
     sgs_errno = errno ? errno : -1;
+#endif
 
   errno = 0;
   if (setgid (gid) != 0)