anchor.diff:      "-DCMAKE_C_COMPILER=${llvmPackages.clang}/bin/clang"
       "-DBoost_USE_STATIC_LIBS=OFF"
       "-DMOZART_BOOST_USE_STATIC_LIBS=OFF"
  -    "-DCMAKE_PROGRAM_PATH=${llvmPackages_4.clang}/bin"
  +    "-DCMAKE_PROGRAM_PATH=${llvmPackages_5.clang}/bin"
       # Rationale: Nix's cc-wrapper needs to see a compile flag (like -c) to
       # infer that it is not a linking call, and stop trashing the command line
       # with linker flags.
  
positive.code: , makeWrapper
  , boost
  , llvmPackages
  , llvmPackages_4
  , gmp
  , emacs
  , emacs25-nox
  
negative.code: 
    buildInputs = [
      boost
      llvmPackages_5.llvm
      llvmPackages_5.clang
      llvmPackages_5.clang-unwrapped
      gmp
      emacs25-nox
      jre_headless
  