Treat texture rectangles as an extension that is enabled be default
diff --git a/glsl_parser_extras.h b/glsl_parser_extras.h
index 51e4eb8..a79dc75 100644
--- a/glsl_parser_extras.h
+++ b/glsl_parser_extras.h
@@ -66,6 +66,8 @@
    /*@{*/
    unsigned ARB_draw_buffers_enable:1;
    unsigned ARB_draw_buffers_warn:1;
+   unsigned ARB_texture_rectangle_enable:1;
+   unsigned ARB_texture_rectangle_warn:1;
    /*@}*/
 };