[GHC] #14946: GHC Calls CPP for HS with -undef

[GHC]

#14946: GHC Calls CPP for HS with -undef
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        Reporter:  Phyx-             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by bgamari):

 erikd says,
 > Phyx-, bgamari-, angerman : the preprocessor should *not* be getting
 called with `-undef` , but it should be getting called with `-Wcpp-undef`
 which warns on undefined macros. see 3cb32d8b0b51c5
 >
 > so adding `-Wcpp-undef` to ghc command line adds `-Wundef` to the CPP
 command line

 That being said, I don't see why this is responsible for the issue that
 Phyx- is seeing as it adds `-Wundef`, not `-undef` (and indeed the commit
 looks right).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14946#comment:3>
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