Add OSX prefix, and be clear that this is OS X only API to avoid any expectation that this API may work elsewhere.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62828 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/toplevel_osx.cpp

@@ -187,12 +187,12 @@ bool wxTopLevelWindowMac::IsActive()
     return m_nowpeer->IsActive();
 }
 
-void wxTopLevelWindowMac::SetModified(bool modified)
+void wxTopLevelWindowMac::OSXSetModified(bool modified)
 {
     m_nowpeer->SetModified(modified);
 }
 
-bool wxTopLevelWindowMac::GetModified() const
+bool wxTopLevelWindowMac::OSXIsModified() const
 {
-    return m_nowpeer->GetModified();
-}
+    return m_nowpeer->IsModified();
+}