cmake HAVE_THR_SETCONCURRENCY examples

alibaba/AliSQL configure.cmake :608 

CHECK_FUNCTION_EXISTS (thr_setconcurrency HAVE_THR_SETCONCURRENCY)

arkdb/arkproxy configure.cmake :408 

CHECK_FUNCTION_EXISTS (thr_setconcurrency HAVE_THR_SETCONCURRENCY)

alibaba/AliSQLBackup configure.cmake :523 

CHECK_FUNCTION_EXISTS (thr_setconcurrency HAVE_THR_SETCONCURRENCY)