Quiet warnings about ir_shader not being handled in places it's not needed.
diff --git a/glsl_parser_extras.cpp b/glsl_parser_extras.cpp
index 4255d2d..4183d13 100644
--- a/glsl_parser_extras.cpp
+++ b/glsl_parser_extras.cpp
@@ -48,6 +48,7 @@
    case vertex_shader:   return "vertex";
    case fragment_shader: return "fragment";
    case geometry_shader: return "geometry";
+   case ir_shader:       break;
    }
 
    assert(!"Should not get here.");