anchor.diff:      ++ optional useQt4 qt4
       ++ optional withQt5 qtbase;
   
  +  depsBuildBuild = [ buildPackages.stdenv.cc ];
  +
     propagatedBuildInputs = optional stdenv.isDarwin ps;
   
     preConfigure = ''
  
positive.code:     # Avoid depending on frameworks.
      ++ optional (!useNcurses) "-DBUILD_CursesDialog=OFF";
  
    dontUseCmakeConfigure = true;
    enableParallelBuilding = true;
  
  
negative.code: { stdenv, fetchurl, fetchpatch, pkgconfig
  , bzip2, curl, expat, libarchive, xz, zlib, libuv, rhash
  , buildPackages
  # darwin attributes
  , ps
  , isBootstrap ? false
  