1. exit() does not make atexit() callbacks.
2. fstat() does not seem to work in MSVC2.0pre-release.
3. Changed TclSetupEnv() so that it does not assume that there is a '='
   in every environment string.  The reason for this is MSVC20 Beta creates
   a bad environment string without any '='.
4. select() with a timeout and no sockets returns immediately instead of
   waiting the time of the timeout.

