The new `reconnect` method introduced new struct members, which clashed with pre-defined names in pre-C99 code.
Another commit forced C99 compilation just to make it work, but of course this is not desirable for outside projects.
Other non-C99 code can now use hiredis as usual again.
Sorry for the inconvenience.

* Fix memory leak in async reply handling (Salvatore Sanfilippo)
* Rename struct member to avoid name clash with pre-c99 code (Alex Balashov, ncopa)