anchor.diff:  #, vo-aacenc
   , vo-amrwbenc ? null
   , wavpack
  -, x11grabExtlib ? false
   , x264
   , x265
   , xavs
  
positive.code:   || samba_client != null
    #|| utvideo != null
    || vid-stab != null
    || x11grabExtlib
    || x264 != null
    || x265 != null
    || xavs != null
  
negative.code: assert libxcbshapeExtlib -> xorg.libxcb != null;
  assert gnutls != null -> openssl == null;
  assert openssl != null -> gnutls == null;
  
  let
    # Minimum/maximun/matching version
  