[GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS

[GHC]

#4934: threadWaitRead works incorrectly on nonthreaded RTS
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        Reporter:  slyfox                       |            Owner:
            Type:  bug                          |           Status:  patch
        Priority:  normal                       |        Milestone:  ⊥
       Component:  Runtime System               |          Version:  7.0.1
      Resolution:                               |         Keywords:
Operating System:  Linux                        |     Architecture:  x86_64
 Type of failure:  Incorrect result at runtime  |  (amd64)
       Test Case:                               |       Difficulty:
        Blocking:                               |  Unknown
                                                |       Blocked By:
                                                |  Related Tickets:
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Comment (by simonmar):

 (b) merge into your patch please.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:24>
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