core/pkgs/by-name/li/libidn2/no-bootstrap-reference.nix

{ stdenv, lib, libidn2, libunistring, runCommandLocal, patchelf }:
# Construct a copy of libidn2.* where all (transitive) libc references (in .bin)
# get replaced by a new one, so that there's no reference to bootstrap tools.
runCommandLocal "${libidn2.pname}-${libidn2.version}" {
  outputs = [ "bin" "dev" "out" ];
  passthru = {
    inherit (libidn2) out info devdoc; # no need to touch these store paths
  };
  inherit (libidn2) meta;
} ''
  cp -r '${libidn2.bin}' "$bin"
  chmod +w "$bin"/bin/*
  patchelf \
    --set-interpreter '${stdenv.cc.bintools.dynamicLinker}' \
    --set-rpath '${
      lib.concatMapStringsSep ":" (p: lib.getLib p + "/lib") [
        stdenv.cc.libc
        libunistring
        libidn2
      ]
    }' \
    "$bin"/bin/*

  cp -r '${libidn2.dev}' "$dev"
  chmod +w "$dev"/nix-support/propagated-build-inputs
  substituteInPlace "$dev"/nix-support/propagated-build-inputs \
    --replace '${libidn2.bin}' "$bin"
  substituteInPlace "$dev"/lib/pkgconfig/libidn2.pc \
    --replace '${libidn2.dev}' "$dev"

  ln -s '${libidn2.out}' "$out" # it's hard to be without any $out
''