anchor.diff:  
     configureFlags = [ "--with-syscmd-shell=${stdenv.shell}" ]
       ++ lib.optional stdenv.hostPlatform.isMinGW "CFLAGS=-fno-stack-protector";
  -
  -  postBuild = ''
  -    makeinfo --html --no-split doc/m4.texi
  -  '';
  -
  -  postInstall = ''
  -    mkdir -p $doc/share/doc/m4
  -    cp ./m4.html $doc/share/doc/m4
  -  '';
   
     meta = {
       description = "GNU M4, a macro processor";
  
positive.code: { lib, stdenv, fetchurl, texinfo4 }:
  
  # Note: this package is used for bootstrapping fetchurl, and thus
  # cannot use fetchpatch! All mutable patches (generated by GitHub or
  
negative.code: stdenv.mkDerivation rec {
    pname = "gnum4";
    version = "1.4.19";
  
    src = fetchurl {
      url = "mirror://gnu/m4/m4-${version}.tar.bz2";
  