Rollback #1185 fix

Rollback #1185 fix

rolling back:

Tue Nov  3 16:05:40 GMT 2009  Simon Marlow <marlowsd@gmail.com>
  * Fix #1185: restart the IO manager after fork()

  This is the libraries/base part of the patch; there is a corresponding
  patch to GHC itself.

  The main change is that we now keep track of the IO manager's ThreadId
  in a top-level MVar, and ensureIOManagerIsRunning checks whether a
  previous IO manager thread is alive before starting one.  In the child
  of fork(), we can hence call ensureIOManagerIsRunning to restart the
  IO manager.

    M ./GHC/Conc.lhs -46 +44

Wed Nov  4 17:49:45 GMT 2009  Ian Lynagh <igloo@earth.li>
  * Fix the build on Windows

    M ./GHC/Conc.lhs -6 +4