Lots of OS/2 fixes mostly to do with painting

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@8940 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/os2/brush.cpp

@@ -204,7 +204,7 @@ bool wxBrush::RealizeResource()
         if (M_BRUSHDATA->m_hBrush==NULL) wxError("Cannot create brush","Internal error") ;
 #endif
         M_BRUSHDATA->m_vBundle.lColor        = vPmColour;
-        M_BRUSHDATA->m_vBundle.lBackColor    = CLR_DEFAULT;
+        M_BRUSHDATA->m_vBundle.lBackColor    = RGB_WHITE;
         M_BRUSHDATA->m_vBundle.usMixMode     = FM_OVERPAINT;
         M_BRUSHDATA->m_vBundle.usBackMixMode = BM_OVERPAINT;