Track and print user defined structure types
diff --git a/glsl_parser_extras.h b/glsl_parser_extras.h
index 55bcc72..125c675 100644
--- a/glsl_parser_extras.h
+++ b/glsl_parser_extras.h
@@ -61,6 +61,10 @@
    /** Loop or switch statement containing the current instructions. */
    class ir_instruction *loop_or_switch_nesting;
 
+   /** List of structures defined in user code. */
+   const glsl_type **user_structures;
+   unsigned num_user_structures;
+
    /**
     * \name Enable bits for GLSL extensions
     */