grutil: Fix missing EXPCL_PANDA_GRUTIL

panda/src/grutil/sceneGraphAnalyzerMeter.h

@@ -36,7 +36,7 @@ class ClockObject;
  * channel or window.  If this is done, it creates a DisplayRegion for itself
  * and renders itself in the upper-right-hand corner.
  */
-class EXPCL_PANDA SceneGraphAnalyzerMeter : public TextNode {
+class EXPCL_PANDA_GRUTIL SceneGraphAnalyzerMeter : public TextNode {
 PUBLISHED:
   explicit SceneGraphAnalyzerMeter(const string &name, PandaNode *node);
   virtual ~SceneGraphAnalyzerMeter();