[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:
            Type:  feature request   |           Status:  new
        Priority:  normal            |        Milestone:  7.8.1
       Component:  Compiler          |          Version:  7.7
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:  #8439
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Comment (by carter):

 The patch nearly works,  I'm having trouble  getting m4/autconf to work
 quite right, could someone who's more familiar with it chime in? I *think*
 once the stuff involving {{{ "$WhatIsHaskellCPPCalled"}}} and {{{
 "$WhatAreCPPFlags" }}}

 is fixed.

 I'm somehow not using the autconf quite correctly to properly instantiate
 the CPP cmd and CPP Flags fields of settings correctly. Some help would be
 appreciated!


 i've also done a test build where i by hand set
 {{{
  ("Haskell CPP command","/Users/carter/bin/gcc"),
  ("Haskell CPP flags","-E -undef -traditional" ),
 }}}

 in my "settings" file after the configure step  ran to validate the rest
 of the build process, and that works (ie testing that if i set it by hand,
 the new /DynFlags.hs etc logic behaves correctly). Namely that I manage to
 get stage2 to build correctly

 sooo, I think all thats left is figuring out what i'm doing wrong on the
 m4/ autoconf front

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8683#comment:6>
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