[GHC] #8683: add "cpp program" and "cpp program options" to settings file

[GHC]

#8683: add "cpp program" and "cpp program options" to settings file
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        Reporter:  carter            |            Owner:  carter
            Type:  feature request   |           Status:  patch
        Priority:  high              |        Milestone:  7.8.3
       Component:  Compiler          |          Version:  7.8.1-rc2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:  9094              |  Related Tickets:  #8439
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Comment (by carter):

 actually mixing clang and gcc is the only way to fix certain issues on OS
 X pre Xcode 5. Its imposible to correctly compile SIMD codes with xcode 4s
 GCC 4.2, so i've had to have custom SETUP.hs files for OS X code that
 invokes clang on c codes, even if ghc is using gcc for its own needs.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8683#comment:63>
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