1 files changed, 3 insertions, 0 deletions
diff --git a/parser.h b/parser.h
index f4054d5a13..e2769a7cca 100644
--- a/parser.h
+++ b/parser.h
@@ -112,6 +112,9 @@ typedef struct yy_parser {
 #define LEX_STUFF_UTF8		0x00000001
 #define LEX_KEEP_PREVIOUS	0x00000002
 
+/* flags for parser API */
+#define PARSE_OPTIONAL          0x00000001
+
 /*
  * Local variables:
  * c-indentation-style: bsd