DC updates and an associated .Def file update

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@9727 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/os2/dcscreen.cpp

@@ -35,11 +35,9 @@ IMPLEMENT_DYNAMIC_CLASS(wxScreenDC, wxWindowDC)
 // Create a DC representing the whole screen
 wxScreenDC::wxScreenDC()
 {
-    // TODO
-}
+    m_hDC = ::WinOpenWindowDC(HWND_DESKTOP);
+    m_hPS = ::WinGetScreenPS(HWND_DESKTOP);
+    ::GpiSetBackMix(m_hPS, BM_LEAVEALONE);
+} // end of wxScreenDC::wxScreenDC()
 
-wxScreenDC::~wxScreenDC()
-{
-    // TODO
-}