anchor.diff:      opengl-dummy
       wayland
       wayland-protocols
  +    zlib
     ];
   
     postPatch = ''
       # Don't build docs.
  -    mkdir -pv docs/_build/html
  +    mkdir -pv docs/_build/html/
       sed -i setup.py \
         -e '/copy_man_pages(ddir)$/d' \
         -e '/copy_html_docs(ddir)$/d'
  
positive.code: , harfbuzz_lib
  , libpng
  , libx11
  , libxcursor
  , libxi
  , libxinerama
  
negative.code:     harfbuzz_lib
      libpng
      libx11
      libxcb
      libxcursor
      libxi
      libxinerama
  