* Update libevent to 2.1.12-stable.
Fixes `kq_init: detected broken kqueue; not using.: Undefined error: 0`
message on start on macOS.
* Do not build libevent samples.
* Explicitly set library type to static on MSVC for libevent.
Co-authored-by: Mitch Livingston <livings124@mac.com>
Co-authored-by: Charles Kerr <charles@charleskerr.com>
Dzmitry Neviadomski