1 files changed, 4 insertions, 0 deletions
diff --git a/enc/gbk.c b/enc/gbk.c
index 31032553bf..3df4e4b6d6 100644
--- a/enc/gbk.c
+++ b/enc/gbk.c
@@ -211,7 +211,11 @@ OnigEncodingDefine(gbk, GBK) = {
   onigenc_not_support_get_ctype_code_range,
   gbk_left_adjust_char_head,
   gbk_is_allowed_reverse_match,
+#ifdef USE_CASE_MAP_API
   onigenc_ascii_only_case_map,
+#else
+  NULL,
+#endif
   0,
   ONIGENC_FLAG_NONE,
 };