anchor.diff:        ${if pulseSupport then "--enable-pulse" else "--disable-pulse"}
         ${optionalString (useUnfreeCodecs && codecs != null) "--codecsdir=${codecs}"}
         ${optionalString (stdenv.isi686 || stdenv.isx86_64) "--enable-runtime-cpudetection"}
  -      --enable-freetype
         --disable-xanim
         --disable-ivtv
         --disable-xvid --disable-xvid-lavc
  
positive.code: { stdenv, fetchurl, freetype, pkgconfig, yasm, freefont_ttf
  , x11Support ? true, libX11 ? null, libXext ? null, mesa ? null
  , xineramaSupport ? true, libXinerama ? null
  , xvSupport ? true, libXv ? null
  
negative.code:   '';
  
    buildInputs = with stdenv.lib;
      [ pkgconfig freetype ]
      ++ optional fontconfigSupport fontconfig
      ++ optionals x11Support [ libX11 libXext mesa ]
      ++ optional alsaSupport alsaLib
      ++ optional xvSupport libXv
  