anchor.diff:  , openexr
   , openh264
   , pango
  +, rtmpdump
   , sbc
   , soundtouch
   , spandsp
  
positive.code:     "-Dopenmpt=disabled" # `libopenmpt` not packaged in nixpkgs as of writing
      "-Dopenni2=disabled" # not packaged in nixpkgs as of writing
      "-Dopensles=disabled" # not packaged in nixpkgs as of writing
      "-Drtmp=disabled" # `librtmp` not packaged in nixpkgs as of writing
      "-Dsctp=disabled" # required `usrsctp` library not packaged in nixpkgs as of writing
      "-Dteletext=disabled" # required `zvbi` library not packaged in nixpkgs as of writing
      "-Dtinyalsa=disabled" # not packaged in nixpkgs as of writing
  
negative.code:     opencv3
      openexr
      openh264
      rtmpdump
      pango
      sbc
      soundtouch
  