implemented wxExecute() for wxDFB; share the implementation with wxX11

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@50834 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/x11/private.h

@@ -80,9 +80,5 @@ extern Window wxGetWindowParent(Window window);
 bool wxSetWMDecorations(Window w, long style);
 bool wxMWMIsRunning(Window w);
 
-// Checks if any of our children are finished.
-// implemented in src/x11/utils.cpp
-void wxCheckForFinishedChildren();
-
 #endif
 // _WX_PRIVATE_H_