anchor.diff:  
     # These arguments are intended as directives to this function and not
     # to be passed through to mkDerivation. They are removed below.
  -  attrsToRemove = ["deps" "flags" "os" "skipOptionalDependencies"
  -                   "passthru" "doCheck" "installDevDependencies" "version"
  +  attrsToRemove = ["deps" "flags" "skipOptionalDependencies"
  +                   "passthru" "doCheck" "includeDevDependencies" "version"
                      "namespace" "patchDependencies" "skipDevDependencyCleanup"]
                      ++ dependencyTypes;
   
  
positive.code:         # that's not required). It will build the package with its dev
          # dependencies. This means that the package must have dev dependencies
          # defined, or it will error.
          env = buildNodePackage (args // {installDevDependencies = true;});
  
          # An 'overrideNodePackage' attribute, which will call
          # `buildNodePackage` with the given arguments overridden.
  
negative.code: 
  in
  
  # Dev dependencies are required to be installed to run unit tests for
  # nearly all packages. Therefore we require that they be installed in
  # order to enable tests.
  if doCheck && (devDependencies == null)
  then throw ("${uniqueName}: Can't run tests because devDependencies have " +
              "not been defined. You can pass in `devDependencies = [];` if " +
              "there are no dev dependencies.")
  else if includeDevDependencies && (devDependencies == null)
  then throw ("${uniqueName}: Can't include dev dependencies since they have " +
              "not been defined. You can pass in `devDependencies = [];` if " +
              "there are no dev dependencies.")
  else
  
  let
  