cmake BSON_HAVE_CLOCK_GETTIME examples

cvet/fonline ThirdParty/mongo-c-driver/src/libbson/CMakeLists.txt :102 

check_symbol_exists (clock_gettime time.h BSON_HAVE_CLOCK_GETTIME)

realm/realm-core src/external/bson/CMakeLists.txt :44 

check_symbol_exists (clock_gettime time.h BSON_HAVE_CLOCK_GETTIME)