cmake HAVE_READ_REAL_TIME examples

alibaba/AliSQL configure.cmake :649 

CHECK_FUNCTION_EXISTS(read_real_time HAVE_READ_REAL_TIME)

arkdb/arkproxy configure.cmake :433 

CHECK_FUNCTION_EXISTS(read_real_time HAVE_READ_REAL_TIME)

alibaba/AliSQLBackup configure.cmake :564 

CHECK_FUNCTION_EXISTS(read_real_time HAVE_READ_REAL_TIME)