2. for the sake of SIGALRM used in the base code, add taos_block_sigalrm and so forth
3. TODO: getaddrinfo would block a few unnecessary seconds when host ~ *.local
         better give warning/suggestion message to user, or just bypass getaddrinfo
         and fail the function

2. initial port of taosd for MacOSX

[TD-2775] <docs>: add update to faq.

Test/td 2695

change version

[TD-2768]<feature>:4x py fetch performance increase

[TD-2758]<fix>: database may always in syncing state because a node is offline

[TD-2606]<enhance>: enlarge TSDB_MAX_WAL_SIZE from 2M to 3M

[TD-2752]<fix>: check if the FILE pointer is valid or not.

Update tscSubquery.c

[TD-2756]<fix>: correct docstring in taos.cfg

avoid repeated subtraction of the number of subqueries.

Docs/update documents for Sprint_112

Release/s111

fix char string overflow