anchor.diff:      (optionalString (enableSharedExecutables && stdenv.isLinux) "--ghc-option=-optl=-Wl,-rpath=$out/lib/${ghc.name}/${pname}-${version}")
       (optionalString (enableSharedExecutables && stdenv.isDarwin) "--ghc-option=-optl=-Wl,-headerpad_max_install_names")
       (optionalString enableParallelBuilding "--ghc-option=-j$NIX_BUILD_CORES")
  -    (optionalString (useCpphs) "--with-cpphs=${cpphs}/bin/cpphs --ghc-options=-cpp --ghc-options=-pgmP${cpphs}/bin/cpphs --ghc-options=-optP--cpp")
  +    (optionalString useCpphs "--with-cpphs=${cpphs}/bin/cpphs --ghc-options=-cpp --ghc-options=-pgmP${cpphs}/bin/cpphs --ghc-options=-optP--cpp")
       (enableFeature enableSplitObjs "split-objs")
       (enableFeature enableLibraryProfiling "library-profiling")
       (enableFeature enableSharedLibraries "shared")
  
positive.code: , enableSharedLibraries ? ((ghc.isGhcjs or false) || stdenv.lib.versionOlder "7.7" ghc.version)
  , enableSplitObjs ? !stdenv.isDarwin # http://hackage.haskell.org/trac/ghc/ticket/4013
  , enableStaticLibraries ? true
  , extraLibraries ? []
  , homepage ? "http://hackage.haskell.org/package/${pname}"
  , hydraPlatforms ? ghc.meta.hydraPlatforms or ghc.meta.platforms
  , hyperlinkSource ? true
  
negative.code: , version, revision ? null
  , sha256 ? null
  , src ? fetchurl { url = "mirror://hackage/${pname}-${version}.tar.gz"; inherit sha256; }
  , buildDepends ? [], libraryHaskellDepends ? [], executableHaskellDepends ? []
  , buildTarget ? ""
  , buildTools ? [], libraryToolDepends ? [], executableToolDepends ? [], testToolDepends ? []
  , configureFlags ? []
  , description ? ""
  , doCheck ? stdenv.lib.versionOlder "7.4" ghc.version
  