{ compiler
, name
, pkgs
, src
}:
let
  # This builds a static PostgREST exectuable based on pkgsStatic.
  # pkgsStatic is based on musl, so is a kind of cross-compilation.
  # We still make this explicit here via pkgsCross, because we need
  # to get postgresql/libpq for musl, too.
  pkgsCross = pkgs.pkgsCross.musl64;
  inherit (pkgsCross) pkgsStatic;
  inherit (pkgsStatic.haskell) lib;

  packagesStatic =
    pkgsStatic.haskell.packages."${compiler}".override (old: {
      ghc = pkgsStatic.pkgsBuildHost.haskell.compiler."${compiler}".override {
        # Using the bundled libffi generally works better for cross-compiling
        libffi = null;
        # Building sphinx fails on some platforms
        enableDocs = false;
        # Cross compiling with native bignum works better than with gmp
        enableNativeBignum = true;
      };

      overrides = pkgs.lib.composeExtensions old.overrides (final: prev: {
        postgresql-libpq = (prev.postgresql-libpq.override {
          # postgresql doesn't build in the fully static overlay - but the default
          # derivation is built with static libraries anyway.
          postgresql = pkgsCross.libpq;
        }).overrideAttrs (finalAttrs: prevAttrs: {
          # Using use-pkg-config flag, because pg_config won't work when cross-compiling
          configureFlags = prevAttrs.configureFlags ++ [ "-fuse-pkg-config" ];
          # Using pkg-config without pkgsCross, because "pkg-config" is hardcoded in
          # postgresql-libpq's Setup.hs. Using pkgsStatic to make pkg-config return the
          # static libs for libpq.
          nativeBuildInputs = prevAttrs.nativeBuildInputs ++ [ pkgs.pkgsStatic.pkg-config ];

          buildInputs = prevAttrs.buildInputs ++ [
            (pkgsStatic.libkrb5.overrideAttrs (finalAttrs: prevAttrs: {
              # disable keyutils dependency, to avoid linking errors
              configureFlags = prevAttrs.configureFlags ++ [ "--without-keyutils" ];
            }))
          ];
        });
      });
    });

  makeExecutableStatic = drv: pkgs.lib.pipe drv [
    (lib.compose.appendConfigureFlags [ "--enable-executable-static" ])
    lib.compose.justStaticExecutables
    (lib.compose.overrideCabal (drv: {
      postInstall = ''
        exe="$out/bin/postgrest"
        if ! (file "$exe" | grep 'statically linked') then
          echo "not a static executable, ldd output:"
          ldd "$exe"
          exit 1
        fi
        "$exe" --help
      '';
    }))
  ];

in
{
  inherit packagesStatic;

  postgrestStatic = makeExecutableStatic (packagesStatic.callCabal2nix name src { });
}