configure.py: pass optimisation flags to seastar/configure.py
configure.py: pass optimisation flags to seastar/configure.py

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