[GHC] #9218: Upgrade the version of MinGW shipped with GHC

[GHC]

#9218: Upgrade the version of MinGW shipped with GHC
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              Reporter:  komadori    |            Owner:  gintas
                  Type:  task        |           Status:  patch
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Build       |          Version:  7.8.2
  System                             |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:  Windows     |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:  #3390
             Test Case:              |
              Blocking:              |
Differential Revisions:  Phab:D339   |
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Comment (by gintas):

 I've run validate.sh on Windows with x86_64 and i686 toolchains, both are
 looking reasonable with kyra's patch. There are some failures, but most of
 them are also there with the baseline.

 I think the only remaining blocker is the mirror location for mingw-w64
 packages on download.haskell.org in case the files on sourceforge are
 removed.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9218#comment:16>
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