deps: c-ares float, manual ares_ssize_t definition

c-ares switched to using ares_ssize_t for platform-independent ssize_t,
our GYP usage to include config/<platform>/ares_config.h causes problems
when including gyp as a library in core, i.e. in env.h and cares_wrap.h,
where the defines don't get pulled in properly. This, so far, is the
easiest approach to just making it work nicely--explicitly defining
ares_ssize_t for the different Windows variants and ssize_t for
non-Windows where we don't have a configured type from an ares_config.h.
In all of our non-Windows platforms it is ssize_t anyway so this is
safe.

PR-URL: https://github.com/nodejs/node/pull/15378


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>