[GHC] #12958: Properly detect if GHCi is running in MinTTY

[GHC]

#12958: Properly detect if GHCi is running in MinTTY
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        Reporter:  RyanGlScott       |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.2.1
       Component:  GHCi              |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Windows           |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2878
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * status:  new => patch
 * differential:   => Phab:D2878


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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12958#comment:1>
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