Fail on invalid token

Reading a zero-length TIdnt token causes infinite loops or other failures.

1 files changed, 2 insertions, 0 deletions

diff --git a/yacc.c b/yacc.c
index 01f054e..8ea5137 100644
--- a/yacc.c
+++ b/yacc.c
@@ -837,6 +837,8 @@ nexttk()
 			die("identifier too long");
 		c = fgetc(fin);
 	}
+	if (p == idnt)
+		die("unknown token");
 	*p = 0;
 	if (strcmp(idnt, "%")==0)
 	if (c=='{')