anchor.diff:    linuxHeaders = common {
       version = "4.18.3";
       sha256 = "1m23hjd02bg8mqnd8dc4z4m3kxds1cyrc6j5saiwnhzbz373rvc1";
  -    # TODO make unconditional next mass rebuild
       patches = [
          ./no-relocs.patch # for building x86 kernel headers on non-ELF platforms
          ./no-dynamic-cc-version-check.patch # so we can use `stdenvNoCC`, see `makeFlags` above
  
positive.code: 
      installPhase = ''
        make headers_install INSTALL_HDR_PATH=$out $makeFlags
  
        # Some builds (e.g. KVM) want a kernel.release.
        mkdir -p $out/include/config
        echo "${version}-default" > $out/include/config/kernel.release
      '';
  
      meta = with lib; {
  
negative.code:     # It may look odd that we use `stdenvNoCC`, and yet explicit depend on a cc.
      # We do this so we have a build->build, not build->host, C compiler.
      depsBuildBuild = [ buildPackages.stdenv.cc ];
      # `elf-header` is null when libc provides `elf.h`.
      nativeBuildInputs = [ perl elf-header ];
  
      extraIncludeDirs = lib.optional stdenvNoCC.hostPlatform.isPowerPC ["ppc"];
  
  