libevent2: Update to 2.1.11
Update libevent to 2.1.11
Use CMake instead GNU Autotools
Backport following commits:
https://github.com/libevent/libevent/commit/
f05ba671931e2b4e38459899f6f63f79f99869fe
..and partially
https://github.com/libevent/libevent/commit/
7201062f3ef505a77baa6ccaf1cf73812462308a
to fix compilation
Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>
(cherry picked from commit
f351beedfd47766e5e44a04af50e3724bec54dbc)
(resolves FS#2435)
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>