gallium: don't call st_flush_bitmap_cache() if the only change is _NEW_PACKUNPACK state

src/mesa/state_tracker/st_atom.c

@@ -148,7 +148,12 @@ void st_validate_state( struct st_context *st )
    struct st_state_flags *state = &st->dirty;
    GLuint i;
 
-   st_flush_bitmap_cache(st);
+   /* The bitmap cache is immune to pixel unpack changes.
+    * Note that GLUT makes several calls to glPixelStore for each
+    * bitmap char it draws so this is an important check.
+    */
+   if (state->mesa & ~_NEW_PACKUNPACK)
+      st_flush_bitmap_cache(st);
 
    check_program_state( st );