/*
 * call-seq:
 *    lineno=(num)
 *
 * Sets the internal line number count that this stream should be set at
 *
 *    reader = Bzip2::Reader.new Bzip2.compress("a\nb")
 *    reader.lineno     # => 0
 *    reader.readline   # => "a\n"
 *    reader.lineno     # => 1
 *    reader.lineno = 0
 *    reader.readline   # => "b"
 *    reader.lineno     # => 1
 *
 * @note This does not actually rewind or move the stream forward
 * @param [Integer] lineno the line number which the stream should consider
 *    being set at
 * @return [Integer] the line number provided
 */
static VALUE bz_reader_set_lineno(VALUE obj, VALUE lineno) {