[GHC] #4989: build error on mingw if pthreads is installed

[GHC]

#4989: build error on mingw if pthreads is installed
---------------------------------+------------------------------------------
    Reporter:  int-e             |        Owner:  simonmar           
        Type:  bug               |       Status:  new                
    Priority:  high              |    Milestone:  7.2.1              
   Component:  Build System      |      Version:  7.1                
    Keywords:                    |     Testcase:                     
   Blockedby:                    |   Difficulty:                     
          Os:  Windows           |     Blocking:                     
Architecture:  Unknown/Multiple  |      Failure:  Building GHC failed
---------------------------------+------------------------------------------
Changes (by simonmar):

  * owner:  => simonmar
  * priority:  normal => high
  * milestone:  => 7.2.1


Comment:

 we should get rid of WANT_NATIVE_WIN32_THREADS and ignore `pthreads.h` on
 Windows.  I'll fix.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4989#comment:1>
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