untangling dc and gc

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42193 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dc.h

@@ -856,6 +856,10 @@ private:
     #include "wx/os2/dc.h"
 #endif
 
+#if wxUSE_GRAPHICS_CONTEXT
+    #include "wx/dcgraph.h"
+#endif
+
 // ----------------------------------------------------------------------------
 // helper class: you can use it to temporarily change the DC text colour and
 // restore it automatically when the object goes out of scope