{ lib, stdenv, fetchurl }:

if stdenv.hostPlatform != stdenv.targetPlatform
then builtins.throw "gnatboot can't cross-compile"
else

stdenv.mkDerivation {
  pname = "gentoo-gnatboot";
  version = "4.1";

  src = if stdenv.hostPlatform.system == "i686-linux" then
    fetchurl {
      url = mirror://gentoo/distfiles/gnatboot-4.1-i386.tar.bz2;
      sha256 = "0665zk71598204bf521vw68i5y6ccqarq9fcxsqp7ccgycb4lysr";
    }
  else if stdenv.hostPlatform.system == "x86_64-linux" then
    fetchurl {
      url = mirror://gentoo/distfiles/gnatboot-4.1-amd64.tar.bz2;
      sha256 = "1li4d52lmbnfs6llcshlbqyik2q2q4bvpir0f7n38nagp0h6j0d4";
    }
  else
    throw "Platform not supported";

  dontStrip = 1;

  installPhase = ''
    mkdir -p $out
    cp -R * $out

    set +e
    for a in $out/bin/* ; do
      patchelf --interpreter $(cat $NIX_CC/nix-support/dynamic-linker) \
        --set-rpath $(cat $NIX_CC/nix-support/orig-libc)/lib:$(cat $NIX_CC/nix-support/orig-cc)/lib64:$(cat $NIX_CC/nix-support/orig-cc)/lib $a
    done
    set -e

    mv $out/bin/gnatgcc_2wrap $out/bin/gnatgcc
    ln -s $out/bin/gnatgcc $out/bin/gcc
  '';

  passthru = {
    langC = true; # TRICK for gcc-wrapper to wrap it
    langCC = false;
    langFortran = false;
    langAda = true;
  };

  meta = with lib; {
    homepage = "https://gentoo.org";
    license = licenses.gpl3Plus;
    maintainers = [ maintainers.lucus16 ];

    platforms = platforms.linux;
  };
}