core/pkgs/build-support/lib/meson.nix

{ stdenv, lib }:

let
  inherit (lib) boolToString optionals;

  # See https://mesonbuild.com/Reference-tables.html#cpu-families
  cpuFamily = platform:
    with platform;
    if isAarch32 then
      "arm"
    else if isx86_32 then
      "x86"
    else
      platform.uname.processor;

  crossFile = builtins.toFile "cross-file.conf" ''
    [properties]
    bindgen_clang_arguments = ['-target', '${stdenv.targetPlatform.config}']
    needs_exe_wrapper = ${
      boolToString (!stdenv.buildPlatform.canExecute stdenv.hostPlatform)
    }

    [host_machine]
    system = '${stdenv.targetPlatform.parsed.kernel.name}'
    cpu_family = '${cpuFamily stdenv.targetPlatform}'
    cpu = '${stdenv.targetPlatform.parsed.cpu.name}'
    endian = ${
      if stdenv.targetPlatform.isLittleEndian then "'little'" else "'big'"
    }

    [binaries]
    llvm-config = 'llvm-config-native'
    rust = ['rustc', '--target', '${stdenv.targetPlatform.rust.rustcTargetSpec}']
  '';

  crossFlags = optionals (stdenv.hostPlatform != stdenv.buildPlatform)
    [ "--cross-file=${crossFile}" ];

  makeMesonFlags = { mesonFlags ? [ ], ... }: crossFlags ++ mesonFlags;

in { inherit makeMesonFlags; }