···241241242242 /* Return a singleton list or an empty list, depending on a boolean
243243 value. Useful when building lists with optional elements
244244- (e.g. `++ optional (system == "i686-linux") flashplayer').
244244+ (e.g. `++ optional (system == "i686-linux") firefox').
245245246246 Type: optional :: bool -> a -> [a]
247247