diff --git a/src/memline.c b/src/memline.c
index 1c2ddbf..2dd465a 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -2542,7 +2542,8 @@
     return ml_append_int(curbuf, lnum, line, len, newfile, FALSE);
 }
 
-#if defined(FEAT_SPELL) || defined(PROTO)
+#if defined(FEAT_SPELL) || (defined(FEAT_QUICKFIX) && defined(FEAT_WINDOWS)) \
+	|| defined(PROTO)
 /*
  * Like ml_append() but for an arbitrary buffer.  The buffer must already have
  * a memline.