Allow using socket from both wxBase and wxCore (adopting to changes from r50831)

Use Unix' gsocketiohandler files for wxBase.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51055 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/os2/apptrait.h

@@ -47,6 +47,9 @@ public:
 #ifdef __WXGTK__
     virtual wxString GetDesktopEnvironment() const;
 #endif
+#if wxUSE_SOCKETS
+    virtual GSocketManager *GetSocketManager();
+#endif
 };
 
 #endif // wxUSE_GUI