Issue with php 8.2.26 and 8.3.13

[bgibson710]

This is the same issue that was fixed in phpipam 7.1.3 phpipam/phpipam#4339

The agent throws errors when attempting to run. I run on PHP 8.2.x branch. I was using 8.2.24 and it ran fine, I updated to 8.2.26 from the remi repo and it broke.

[bgibson710]

FWIW I don't know how to do a pull request, but I was able to fix this by changing line 1663 in functions/classes/class.Subnets.php to
$pwr = gmp_pow2(128-$x);

And then copied the function in global-functions from the previously linked issue into functions/global-functions.php
function gmp_pow2(int $exp) : GMP { $result = gmp_init(0); gmp_setbit($result, $exp); return $result; }