[GHC] #12715: T3994 is intermittently broken on Windows

[GHC]

#12715: T3994 is intermittently broken on Windows
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        Reporter:  bgamari       |                Owner:
            Type:  bug           |               Status:  new
        Priority:  normal        |            Milestone:  8.2.1
       Component:  Test Suite    |              Version:  8.1
      Resolution:                |             Keywords:
Operating System:  Windows       |         Architecture:  x86_64 (amd64)
 Type of failure:  None/Unknown  |            Test Case:
      Blocked By:                |             Blocking:
 Related Tickets:                |  Differential Rev(s):
       Wiki Page:                |
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Comment (by bgamari):

 It looks like `T1372` sometimes fails in a similar way,
 {{{
 +++ ./driver/T1372/T1372.run/T1372.run.stderr.normalised        2016-10-16
 03:38:08.773888500 +0000
 @@ -1,2 +1,5 @@
 +      4 [main] make (39172) C:/msys64/usr/bin/make: *** fatal error in
 forked process - CreateFileMapping cygpid.39172, Win32 error 5.
 Terminating.
 +      4 [main] make 21144 fork: child -1 - forked process 39172 died
 unexpectedly, retry 0, exit code 0xC0000142, errno 11
 +make[3]: C:/msys64/home/drydock/ghc/testsuite/mk/boilerplate.mk:180:
 fork: Resource temporarily unavailable
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12715#comment:1>
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