if (match) {
        return "https://golang.org/change/" + match[1];
    }

    if (pkgRE.test(t)) {
        // TODO: make this smarter, using a list of packages + substring matches.
        // Get the list from godoc itself in JSON format?
        return "https://golang.org/pkg/" + t;
    }

    return null;

			read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
			readdir(path, callback) { callback(enosys()); },
			readlink(path, callback) { callback(enosys()); },
			rename(from, to, callback) { callback(enosys()); },
			rmdir(path, callback) { callback(enosys()); },
			stat(path, callback) { callback(enosys()); },
			symlink(path, link, callback) { callback(enosys()); },