if s == "" {
		return def
	}
	return s
}

// An ImportMode controls the behavior of the Import method.
type ImportMode uint

const (
	// If FindOnly is set, Import stops after locating the directory
	// that should contain the sources for a package. It does not
	// read any files in the directory.
	FindOnly ImportMode = 1 << iota

	// If AllowBinary is set, Import can be satisfied by a compiled