Added configure check for getbkgd and define HAVE_GETBKGD.

diff --git a/include/acconfig.h b/include/acconfig.h
index e2b7616..cf93e71 100644
--- a/include/acconfig.h
+++ b/include/acconfig.h
@@ -69,6 +69,9 @@
 /* Define if ncurses have the new resizeterm function */
 #undef HAVE_RESIZETERM
 
+/* Define if ncurses have the new getbkgd function */
+#undef HAVE_GETBKGD
+
 /* Define if we can a compatible xterm program */
 #undef XTERM_PROGRAM