adapting to new inheritance of wxMemoryDC (under MSW only at the moment)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43110 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/graphcmn.cpp

@@ -707,6 +707,12 @@ wxGraphicsContext* wxGraphicsContext::Create( const wxWindowDC& dc)
 {
     return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(dc);
 }
+#ifdef __WXMSW__
+wxGraphicsContext* wxGraphicsContext::Create( const wxMemoryDC& dc) 
+{
+    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(dc);
+}
+#endif
 
 wxGraphicsContext* wxGraphicsContext::CreateFromNative( void * context )
 {