[GHC] #13008: Cleanup backwards compatibility ifdefs due to stage1 external interpreter work

[GHC]

#13008: Cleanup backwards compatibility ifdefs due to stage1 external interpreter
work
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           Reporter:  shlevy         |             Owner:
               Type:  task           |            Status:  new
           Priority:  normal         |         Milestone:  8.4.1
          Component:  Compiler       |           Version:  8.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 https://phabricator.haskell.org/D2826 and
 https://phabricator.haskell.org/D2884 make some code paths that were
 incompatible with GHC 7.10.x newly built by the stage0 compiler, requiring
 some CPP hackery to keep our compatibility guarantees. When we can drop
 that dependency, we should be sure to remove the old code paths.

 Specifically, the checks for MIN_VERSION_base(4,9,0) and
 MIN_VERSION_process(1,4,2) can be removed once we're able to assume ghc
 8.0.x as stage0.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13008>
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