anchor.diff:  { stdenv, lib, buildPackages, fetchurl, fetchpatch
   , enableStatic ? false
   , enableMinimal ? false
  -, useMusl ? false, musl
  +, useMusl ? stdenv.hostPlatform.libc == "musl", musl
   , extraConfig ? ""
   , buildPlatform, hostPlatform
   }:
  +
  +assert stdenv.hostPlatform.libc == "musl" -> useMusl;
   
   let
     configParser = ''
  
positive.code: 
      ${extraConfig}
      CONFIG_CROSS_COMPILER_PREFIX "${stdenv.cc.targetPrefix}"
      EOF
  
      make oldconfig
  
negative.code:     }
    '';
  
    libcConfig = lib.optionalString useMusl ''
      CONFIG_FEATURE_UTMP n
      CONFIG_FEATURE_WTMP n
    '';
  in
  
  stdenv.mkDerivation rec {
  