fileutils.FindDir looks for the given directory in nearby ancestors relative to the current working directory as well as the directory of the executable, falling back to `./` if not found.

FindDirRelBinary looks for the given directory in nearby ancestors relative to the directory of the executable, then relative to the working directory, falling back to `./` if not found.

FindFile looks for the given file in nearby ancestors relative to the current working directory as well as the directory of the executable.