clang wrapper for GHC 7.6.3 and OS X 10.9

clang-xcode5-wrapper.hs

import System.Environment
import System.Process
import Data.List (isInfixOf)

-- | This script wraps clang to pass it essential arguments that keep it from dying when
-- GHC uses it as a C pre-processor during the build process.
-- To use it, choose the version of clang you'd like to use,
-- (GHC-iOS needs to use Xcode5's clang, which is already set here)
-- then compile it (ghc clang-xcode5-wrapper.hs).
-- Then, find your GHC settings file (usually something like /usr/local/lib/ghc-7.6.3/settings)
-- and change the "C compiler command" to point to the resultant wrapper executable.

-- N.B. you can also just put it in your PATH, which lets you refer to it simply
-- as "clang-xcode5-wrapper" in GHC settings and "./configure --with-gcc=clang-xcode5-wrapper"

clang = "/usr/bin/clang" -- system clang

flags =
	[ "-Wno-invalid-pp-token"
	, "-Wno-unicode"
	, "-Wno-trigraphs"
	]

-- See if we're in preprocessor mode
check args
	| and (map (`elem` args) ["-E","-undef","-traditional"]) = replace args
	| otherwise = args

-- make sure we use assembler-with-cpp
replace ("-x":"c":xs) = "-P":"-x":"assembler-with-cpp":replace xs
replace (x:xs) = x:replace xs
replace [] = []

main = do
	args <- getArgs
	rawSystem clang $ flags ++ (check args)