Add the unified style on OS X 10.4, and default to using it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48165 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/mac/carbon/toplevel.h

@@ -100,6 +100,7 @@ public:
     virtual void MacInstallTopLevelWindowEventHandler() ;
 
     bool MacGetMetalAppearance() const ;
+    bool MacGetUnifiedAppearance() const ;
 
     void MacChangeWindowAttributes( wxUint32 attributesToSet , wxUint32 attributesToClear ) ;
     wxUint32 MacGetWindowAttributes() const ;
@@ -136,6 +137,7 @@ private :
     // This is because the ExtraStyle flags get out of sync with the metal appearance and the metal
     // logic & checks cease to work as expected. To set the metal appearance, use SetExtraStyle.
     void MacSetMetalAppearance( bool on ) ;
+    void MacSetUnifiedAppearance( bool on ) ;
 
     WXEVENTHANDLERREF    m_macEventHandler ;