php bcround implementation polyfill for php <8.4

bcround.php

<?php

if (! function_exists('bcround')) {
  /**
   * @param numeric-string $num
   * @param value-of<\RoundingMode::*> $mode
   * @return numeric-string
   */
  function bcround(string $num, int $precision, int $mode = \RoundingMode::HalfAwayFromZero): string {
    return \bcadd((string) \round((float) $num, $precision, $mode), '0', $precision);
  }
}