[GHC] #12171: cygwin - option to accept ISO C99... unsupported

[GHC]

#12171: cygwin - option to accept ISO C99... unsupported
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        Reporter:  wozgonon             |                Owner:
            Type:  bug                  |               Status:  new
        Priority:  normal               |            Milestone:
       Component:  Build System         |              Version:  8.0.1
      Resolution:                       |             Keywords:
Operating System:  Windows              |         Architecture:  x86
 Type of failure:  Building GHC failed  |            Test Case:
      Blocked By:                       |             Blocking:
 Related Tickets:                       |  Differential Rev(s):
       Wiki Page:                       |
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Comment (by thomie):

 Cygwin isn't supported. Please use `msys2` as described here:
 [wiki:Building/Preparation/Windows], and reported any problems you might
 run into.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12171#comment:2>
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