glcpp: Build a reentrant parser.
diff --git a/glcpp/glcpp.h b/glcpp/glcpp.h
index 0d43f0b..3441ab8 100644
--- a/glcpp/glcpp.h
+++ b/glcpp/glcpp.h
@@ -163,7 +163,7 @@
 glcpp_lex_set_source_string(glcpp_parser_t *parser, const char *shader);
 
 int
-glcpp_lex (yyscan_t scanner);
+glcpp_lex (YYSTYPE *lvalp, yyscan_t scanner);
 
 int
 glcpp_lex_destroy (yyscan_t scanner);