anchor.diff:    patchFlags = "-p0";
   
     patches = upstreamPatches
  -    ++ optional stdenv.hostPlatform.isCygwin ./cygwin-bash-4.4.11-2.src.patch
  -    # https://lists.gnu.org/archive/html/bug-bash/2016-10/msg00006.html
  -    ++ optional stdenv.hostPlatform.isMusl (fetchurl {
  -      url = "https://lists.gnu.org/archive/html/bug-bash/2016-10/patchJxugOXrY2y.patch";
  -      sha256 = "1m4v9imidb1cc1h91f2na0b8y9kc5c5fgmpvy9apcyv2kbdcghg1";
  -    });
  +    ++ optional stdenv.hostPlatform.isCygwin ./cygwin-bash-4.4.11-2.src.patch;
   
     configureFlags = [
       (if interactive then "--with-installed-readline" else "--disable-readline")
  
positive.code: { stdenv, buildPackages
  , fetchurl, binutils ? null, bison, autoconf, utillinux
  
  # patch for cygwin requires readline support
  , interactive ? stdenv.isCygwin, readline80 ? null
  
negative.code:   depsBuildBuild = [ buildPackages.stdenv.cc ];
    nativeBuildInputs = [ bison ]
      ++ optional withDocs texinfo
      ++ optional stdenv.hostPlatform.isDarwin binutils;
  
    buildInputs = optional interactive readline80;
  
  