[GHC] #8528: Preprocessor issues building GHC HEAD on Mavericks

[GHC]

#8528: Preprocessor issues building GHC HEAD on Mavericks
----------------------------------------+----------------------------------
        Reporter:  guest                |            Owner:
            Type:  bug                  |           Status:  new
        Priority:  high                 |        Milestone:
       Component:  Compiler             |          Version:  7.7
      Resolution:                       |         Keywords:  clang
Operating System:  MacOS X              |     Architecture:  x86_64 (amd64)
 Type of failure:  Building GHC failed  |       Difficulty:  Unknown
       Test Case:                       |       Blocked By:
        Blocking:                       |  Related Tickets:  #8480
----------------------------------------+----------------------------------

Comment (by hvr):

 Replying to [comment:7 simonmar]:
 > I'm without a clue about what the problem is and how to fix it, and I
 don't have a Mac.  Pull requests gladly accepted :-)

 One of the problems is that tradional CPP has different semantics, GNU cpp
 has the `-Wtraditional` flag that warns about some problematic constructs
 which differ between traditional/non-traditional CPP mode, e.g. assume the
 following `foo.hs` file:

 {{{
  #if __GLASGOW_HASKELL__ > 706
  -- ...
  #endif
 }}}

 then `cpp -Wtraditional foo.hs` would explain that

 {{{
 # 1 "foo.hs"
 foo.hs:1:3: warning: traditional C ignores #if with the # indented
 [-Wtraditional]
   #if __GLASGOW_HASKELL__ > 706
    ^
 foo.hs:3:3: warning: traditional C ignores #endif with the # indented
 [-Wtraditional]
   #endif
    ^
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8528#comment:8>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler