nixpkgs/pkgs/build-support/gcc-cross-wrapper/default.nix

# The Nix `gcc' stdenv.mkDerivation is not directly usable, since it doesn't
# know where the C library and standard header files are.  Therefore
# the compiler produced by that package cannot be installed directly
# in a user environment and used from the command line.  This
# stdenv.mkDerivation provides a wrapper that sets up the right environment
# variables so that the compiler and the linker just "work".

{ name ? "", stdenv, nativeTools, nativeLibc, noLibc ? false, nativePrefix ? ""
, gcc ? null, libc ? null, binutils ? null, shell ? "", cross
}:

assert nativeTools -> nativePrefix != "";
assert !nativeTools -> gcc != null && binutils != null;
assert !noLibc -> (!nativeLibc -> libc != null);

let
  chosenName = if name == "" then gcc.name else name;
  gccLibs = stdenv.mkDerivation {
    name = chosenName + "-libs";
    phases = [ "installPhase" ];
    installPhase = ''
      ensureDir $out
      cp -Rd ${gcc}/lib $out/lib
      if [ -d ${gcc}/lib64 ]; then
          cp -Rd ${gcc}/lib64 $out/lib64
      fi
    '';
  };
in
stdenv.mkDerivation {
  builder = ./builder.sh;
  setupHook = ./setup-hook.sh;
  gccWrapper = ./gcc-wrapper.sh;
  ldWrapper = ./ld-wrapper.sh;
  utils = ./utils.sh;
  addFlags = ./add-flags;
  inherit nativeTools nativeLibc nativePrefix gcc libc binutils;
  crossConfig = if (cross != null) then cross.config else null;
  gccLibs = if gcc != null then gccLibs else null;
  name = chosenName;
  langC = if nativeTools then true else gcc.langC;
  langCC = if nativeTools then true else gcc.langCC;
  langF77 = if nativeTools then false else gcc ? langFortran;
  shell = if shell == "" then stdenv.shell else shell;
  meta = if gcc != null then gcc.meta else
    { description = "System C compiler wrapper";
    };

  passthru = {
    target = cross;
  };
}