cmake HAVE_SIGTHREADMASK examples

alibaba/AliSQL configure.cmake :575 

CHECK_FUNCTION_EXISTS (sigthreadmask HAVE_SIGTHREADMASK)

arkdb/arkproxy configure.cmake :391 

CHECK_FUNCTION_EXISTS (sigthreadmask HAVE_SIGTHREADMASK)

alibaba/AliSQLBackup configure.cmake :490 

CHECK_FUNCTION_EXISTS (sigthreadmask HAVE_SIGTHREADMASK)