cmake HAVE_THR_YIELD examples

arkdb/inception configure.cmake :502 

CHECK_FUNCTION_EXISTS (thr_yield HAVE_THR_YIELD)

alibaba/AliSQL configure.cmake :609 

CHECK_FUNCTION_EXISTS (thr_yield HAVE_THR_YIELD)

Tokutek/mysql-5.5 configure.cmake :442 

CHECK_FUNCTION_EXISTS (thr_yield HAVE_THR_YIELD)