diff --git a/acconfig.h b/acconfig.h
index cb7bcba0..ae3e8ec0 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -21,6 +21,7 @@
 #undef SCO_FLAVOR
 
 /* our own curses checks */
+#undef USE_CURSES_WINDOWS
 #undef HAVE_NCURSES_USE_DEFAULT_COLORS
 #undef HAVE_CURSES_IDCOK
 #undef HAVE_CURSES_RESIZETERM