now compiles with USE_XPM_IN_MSW on

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@123 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/bitmap.h

@@ -131,6 +131,7 @@ public:
   wxBitmap(const char bits[], const int width, const int height, const int depth = 1);
 
 #if USE_XPM_IN_MSW
+  class wxItem;
   // Initialize with XPM data
   wxBitmap(const char **data, wxItem *anItem = NULL);
 #endif