function lastPage( opt, last ) {
	if (
		opt !== 'last' &&
		opt < last
	) {
		last = opt;
	}
	return last;
}
Determines the last page to resolve.

@private
@param {(PositiveInteger|string)} opt - last page option
@param {PositiveInteger} last - last linked page
@returns {PositiveInteger} last page to resolve