anchor.diff:          meson
           ninja
           pkg-config
  +        python3Packages.sphinx
  +        doxygen
         ];
   
         # Otherwise, the meson log says:
  
positive.code: # Tag support
  , libid3tag
  , nixosTests
  # For tests
  , gtest
  , fetchpatch # used to fetch an upstream patch fixing a failing test
  
negative.code: 
        mesonAutoFeatures = "disabled";
  
        outputs = [ "out" "doc" "man" ];
  
        mesonFlags = [
          # Documentation is enabled unconditionally but it's not installed
          # unconditionally thanks to the outputs being split
          "-Ddocumentation=true"
          "-Dtest=true"
        ]
          ++ map (x: "-D${x}=enabled") features_
  