[GHC] #13636: Enable -Wcpp-undef

[GHC]

#13636: Enable -Wcpp-undef
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"6267d8c9e54663a23f0ac13556522a53580d0910/ghc"
 6267d8c9/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="6267d8c9e54663a23f0ac13556522a53580d0910"
 Enable -Wcpp-undef for GHC and runtime system

 This gets us much of the benefit of enabling it globally, which avoiding
 (at least for now) the pain of making the core libraries build as well.
 See #13636.

 Test Plan: Validate

 Reviewers: erikd, austin

 Subscribers: rwbarton, thomie

 GHC Trac Issues: #13636

 Differential Revision: https://phabricator.haskell.org/D3517
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13636#comment:2>
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