wllvm.nix

{ nixpkgs ? import (import /home/doc/git/allvm-tools/nix/fetch-nixpkgs.nix) { }
}:

let
  overlay = self: super: {
    stdenv = super.overrideCC (nixpkgs.stdenv) (with nixpkgs;
      wrapCCWith {
        cc = wllvm;
        extraBuildCommands = ''
          echo CC=wllvm >> $out/nix-support/setup-hook
          echo CXX=wllvm++ >> $out/nix-support/setup-hook
          echo export LLVM_COMPILER=clang >> $out/nix-support/setup-hook
          echo export PATH=${
            lib.makeBinPath (with llvmPackages_4; [ clang llvm file ])
          }:$PATH >> $out/nix-support/setup-hook
        '';
      });
  };
  nixpkgs' = import <nixpkgs> { overlays = [ overlay ]; };
  libc = nixpkgs'.stdenv.mkDerivation {
    name = "musl";
    preConfigure = ''
      export WLLVM_CONFIGURE_ONLY=1
    '';
    postConfigure = ''
      unset WLLVM_CONFIGURE_ONLY
    '';
    configureFlags = [ "--target=LLVM" "--build=LLVM" ];
    src = builtins.fetchurl
      "https://github.com/SRI-CSL/musllvm/archive/master.tar.gz";
  };
  overlay' = self: super: {
    stdenv = nixpkgs'.stdenv.override {
      cc = nixpkgs'.stdenv.cc.override {
        inherit libc;
        bintools = nixpkgs'.stdenv.cc.bintools.override { inherit libc; };
      };
    };
  };
in import <nixpkgs> { overlays = [ overlay' ]; }