- Added wxAddProcessCallbackForPid function

- Don't create pipeEndProcDetect on Darwin
- Initialize the wxEndProcessData before installing the callback
- Implement wxAddProcessCallbackForPid for Darwin, the code started life
  as an example from ADC and certainly has its fair share of race
  conditions, but with a few hacks it seems to be working okay.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@19811 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/unix/execute.h

@@ -28,5 +28,7 @@ extern void wxHandleProcessTermination(wxEndProcessData *proc_data);
 // this function is called to associate the port-specific callback with the
 // child process. The return valus is port-specific.
 extern int wxAddProcessCallback(wxEndProcessData *proc_data, int fd);
+// For ports (e.g. DARWIN) which can add callbacks based on the pid
+extern int wxAddProcessCallbackForPid(wxEndProcessData *proc_data, int pid);
 
 #endif // _WX_UNIX_EXECUTE_H