empire thread debugging for Windows build.
(empth_select) [_WIN32]: Fix empth_select() so can be aborted.
The bug was that a command would not be aborted during an update.
The problem was select() was not interrupt by the setting of the
signalling wakeup event. Fix by replacing the select() with
WSAEventSelect().
(empth_exit) [_WIN32]:
Fix the shutdown sequence for Windows build to be running in
empth_t context. Add a loc_RunThisThread() in empth_exit()
before starting the shutdown() sequence.
1bbd7e5342