--- window.orig.c	2016-03-30 16:36:29.026280200 -0700
+++ window.c	2016-03-30 16:38:33.406674800 -0700
@@ -6746,7 +6746,7 @@
     m->match.regprog = regprog;
     m->match.rmm_ic = FALSE;
     m->match.rmm_maxcol = 0;
-#ifdef FEAT_CONCEAL
+#if defined(FEAT_CONCEAL) && defined(FEAT_MBYTE)
     m->conceal_char = 0;
     if (conceal_char != NULL)
 	m->conceal_char = (*mb_ptr2char)(conceal_char);