fixing warning in osx core and carbon

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59777 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/carbon/renderer.cpp

@@ -38,6 +38,7 @@
 // check if we're currently in a paint event
 inline bool wxInPaintEvent(wxWindow* win, wxDC& dc)
 {
+    wxUnusedVar(dc);
     return ( win->MacGetCGContextRef() != NULL );
 }