logalloc: define segment_zone::maximum_size
logalloc: define segment_zone::maximum_size

Yield build errors with some compilers, if missing.

scylladb/scylla,duarten/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,duarten/scylla,scylladb/scylla