build: group "CMAKE_CXX_*" options together
build: group "CMAKE_CXX_*" options together

for better readability and maintanablity

Signed-off-by: Kefu Chai <cdc92d111bae0ed1ee3b3c8a1f849fcffc6b44f7@gmail.com>
Message-Id: <20220524234427.29150-2-cdc92d111bae0ed1ee3b3c8a1f849fcffc6b44f7@gmail.com>

syuu1228/seastar,avikivity/seastar,scylladb/seastar,avikivity/seastar,syuu1228/seastar,avikivity/seastar,scylladb/seastar,syuu1228/seastar,scylladb/seastar