As described in the previous commit, GCC 15 uses C23 by default and that
changes the meaning of such argument-less function declarations. So
whenever we assign such a function to a pointer that expects a function
with arguments it causes an incompatible pointer type warning. We
could define dedicated functions/callbacks whenever necessary, but this
seems like the simpler approach for now (especially since most uses of
these functions have already been cast).
This is particularly important for higher number of segments, but even
with small numbers there is a significant difference. For instance,
with 4 segments the fourth segment had no IPs assigned with the old
code, no matter how large the pool, because none of the eight bits used
for the segment check hashed/mapped to it.
If the provider has access to the full pool list, it can enumerate
them twice, for example to search for existing leases first, and
only search for new leases in a second step.
Fixes lease enumeration in attr-sql using multiple pools.
Tobias Brunner