[GHC] #8943: Add System.Process.createPipe

[GHC]

#8943: Add System.Process.createPipe
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       Reporter:  tibbe              |             Owner:
           Type:  feature request    |            Status:  new
       Priority:  normal             |         Milestone:  7.10.1
      Component:  libraries/process  |           Version:  7.6.3
       Keywords:                     |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple   |   Type of failure:  None/Unknown
     Difficulty:  Unknown            |         Test Case:
     Blocked By:                     |          Blocking:
Related Tickets:                     |
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 As agreed in:
 http://comments.gmane.org/gmane.comp.lang.haskell.libraries/21373

 I've validated the patch on OS X, but I need someone to validate on
 Windows. I originally wrote this code for cabal and tested it on all
 platforms back then. I no longer have a Windows machine and the imports in
 `System.Process` are messy enough that someone needs to check that it
 still builds on Windows.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8943>
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