pkgs: stdenv:
let
  inherit (pkgs.lib) optionalAttrs optionals toList;
  inherit (pkgs) addAttrsToDerivation overrideCC;
  inherit (pkgs.llvmPackages_latest) clangUseLLVM bintools;
  inherit (stdenv) buildPlatform hostPlatform;

  cflags = [
    "-pipe"  # Prefer pipes over temporary files between stages
    "-O2"
#  ] ++ optionals buildPlatform.useLLVM [
    "-flto=thin"
  ];

  ldflags = [
    "-O2"  # Enable tail merging of strings
    "--hash-style=gnu"  # Produce only DT_GNU_HASH
#  ] ++ optionals buildPlatform.useLLVM [
    "--icf=safe"  # Fold identical code where safe
    "--lto-O2"
    "--pack-dyn-relocs=relr"
  ];

  rustflags = [
    "-C opt-level=2"
#  ] ++ optionals buildPlatform.useLLVM [
    "-C lto=thin"
    "-C linker-flavor=ld.lld"
    "-C linker-plugin-lto"
  ] ++ optionals (hostPlatform.isx86_64 && hostPlatform ? gcc.arch) [
    "-C target-cpu=${hostPlatform.gcc.arch}"
  ] ++ map (flag: "-C link-arg=${flag}") ldflags;

in addAttrsToDerivation (base: {
  env = (base.env or { }) // optionalAttrs (!base ? NIX_CFLAGS_COMPILE) {
    NIX_CFLAGS_COMPILE =
      toString (toList base.env.NIX_CFLAGS_COMPILE or [ ] ++ cflags);
  } // optionalAttrs (base ? env.NIX_LDFLAGS) {
    NIX_LDFLAGS =
      toString (toList base.env.NIX_LDFLAGS or [ ] ++ ldflags);
  };

  NIX_CFLAGS_LINK = toList base.NIX_CFLAGS_LINK or [ ] ++ map (flag: "-Wl,${flag}") ldflags;
  NIX_RUSTFLAGS = toList base.NIX_RUSTFLAGS or [ ] ++ rustflags;
} // optionalAttrs (base ? env.NIX_CFLAGS) {
  NIX_CFLAGS_COMPILE = toList base.NIX_CFLAGS_COMPILE or [ ] ++ cflags;
} // optionalAttrs (!base ? env.NIX_LDFLAGS) {
  NIX_LDFLAGS = toList base.NIX_LDFLAGS or [ ] ++ ldflags;
}) (overrideCC stdenv (clangUseLLVM.override { inherit bintools; }))