[GHC] #10726: Upgrade MingW-w64 distributions for windows

[GHC]

#10726: Upgrade MingW-w64 distributions for windows
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        Reporter:  Phyx-             |                Owner:
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  7.10.3
       Component:  Build System      |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Windows           |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #9218 #9014       |  Differential Rev(s):  Phab:D1123
  #10435                             |
       Wiki Page:                    |
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Comment (by Phyx-):

 Yes, sorry, I was confused as to why the runtime linker was involved
 during a normal compilation. But `TH` makes sense.

 I guess a temporary solution to get `7.10.3` out the door is to just re-
 export everything from `mingwex` since you can't actually specify
 `-lmingwex` current.

 But I have wondered and still do why the RTS is re-exporting symbols like
 this instead of us just linking against `-lmingwex`. Do you have an idea
 why @awson?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10726#comment:39>
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