cmake uring examples

facebook/rocksdb CMakeLists.txt :333 

find_package(uring)

ceph/ceph CMakeLists.txt :276 

find_package(uring REQUIRED)

topling/toplingdb CMakeLists.txt :333 

find_package(uring)

speedb-io/speedb CMakeLists.txt :361 

find_package(uring)

ververica/ForSt CMakeLists.txt :315 

find_package(uring)

apple/foundationdb fdbserver/CMakeLists.txt :17 

find_package(uring)

syslog-ng/syslog-ng CMakeLists.txt :313 

find_package(uring)