Pull up following revision(s) via patch (requested by spz in ticket #478):
external/bsd/libevent/dist/ChangeLog          up to 1.1.1.2
external/bsd/libevent/dist/Makefile.am        up to 1.1.1.1
external/bsd/libevent/dist/Makefile.in        up to 1.1.1.1
external/bsd/libevent/dist/aclocal.m4          up to 1.1.1.1
external/bsd/libevent/dist/arc4random.c        up to 1.1.1.1
external/bsd/libevent/dist/buffer.c            up to 1.2
external/bsd/libevent/dist/bufferevent.c      up to 1.2
external/bsd/libevent/dist/bufferevent_pair.c  up to 1.1.1.1
external/bsd/libevent/dist/bufferevent_sock.c  up to 1.1.1.1
external/bsd/libevent/dist/compile            up to 1.1.1.1
external/bsd/libevent/dist/config.guess        up to 1.1.1.1
external/bsd/libevent/dist/config.h.in        up to 1.1.1.1
external/bsd/libevent/dist/config.sub          up to 1.1.1.1
external/bsd/libevent/dist/configure          up to 1.1.1.1
external/bsd/libevent/dist/configure.ac         up to 1.1.1.1
external/bsd/libevent/dist/m4/ac_backport_259_ssizet.m4 up to 1.1.1.1
external/bsd/libevent/dist/depcomp            up to 1.1.1.1
external/bsd/libevent/dist/epoll_sub.c        up to 1.1.1.1
external/bsd/libevent/dist/evbuffer-internal.h up to 1.2
external/bsd/libevent/dist/evdns.c            up to 1.2
external/bsd/libevent/dist/event.c            up to 1.2
external/bsd/libevent/dist/event_iocp.c        up to 1.1.1.1
external/bsd/libevent/dist/event_tagging.c    up to 1.2
external/bsd/libevent/dist/evrpc.c            up to 1.2
external/bsd/libevent/dist/evthread_win32.c    up to 1.1.1.1
external/bsd/libevent/dist/evutil.c            up to 1.4
external/bsd/libevent/dist/evutil_rand.c      up to 1.2
external/bsd/libevent/dist/http.c              up to 1.2
external/bsd/libevent/dist/install-sh          up to 1.1.1.1
external/bsd/libevent/dist/listener.c          up to 1.1.1.1
external/bsd/libevent/dist/log-internal.h      up to 1.3
external/bsd/libevent/dist/log.c              up to 1.2
external/bsd/libevent/dist/ltmain.sh          up to 1.1.1.1
external/bsd/libevent/dist/missing            up to 1.1.1.1
external/bsd/libevent/dist/util-internal.h    up to 1.2
external/bsd/libevent/dist/win32select.c      up to 1.1.1.1
external/bsd/libevent/dist/WIN32-Code/event2/event-config.h up to 1.1.1.1
external/bsd/libevent/dist/include/Makefile.in up to 1.1.1.1
external/bsd/libevent/dist/include/event2/buffer.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/buffer_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/bufferevent.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/bufferevent_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/bufferevent_ssl.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/bufferevent_struct.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/dns.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/dns_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/dns_struct.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/event.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/event_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/event_struct.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/http.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/http_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/http_struct.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/keyvalq_struct.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/listener.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/rpc.h up to 1.2
external/bsd/libevent/dist/include/event2/rpc_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/rpc_struct.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/tag.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/tag_compat.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/thread.h up to 1.1.1.1
external/bsd/libevent/dist/include/event2/util.h up to 1.2
external/bsd/libevent/dist/sample/Makefile.in  up to 1.1.1.1
external/bsd/libevent/dist/sample/http-server.c up to 1.1.1.1
external/bsd/libevent/dist/test/Makefile.am    up to 1.1.1.1
external/bsd/libevent/dist/test/Makefile.in    up to 1.1.1.1
external/bsd/libevent/dist/test/regress.c      up to 1.7
external/bsd/libevent/dist/test/regress.h      up to 1.3
external/bsd/libevent/dist/test/regress_buffer.c up to 1.3
external/bsd/libevent/dist/test/regress_http.c up to 1.3

Update libevent to 2.0.22-stable (5 Jan 2015)
SECURITY FIXES (evbuffers)
o Avoid integer overflow bugs in evbuffer_add() and related functions.
  See CVE-2014-6272 advisory for more information.
  (20d6d4458bee5d88bda1511c225c25b2d3198d6c)

BUGFIXES (evhttp)
o fix #73 and fix http_connection_fail_test to catch it (crash fix)
  (b618204 Greg Hazel)
o Avoid racy bufferevent activation (5eb1788 Nate Rosenblum)

BUGFIXES (resource leaks/lock errors on error)
o Avoid leaking fds on evconnlistener with no callback set (69db261)
o Avoid double-close on getsockname error in evutil_ersatz_socketpair
  (0a822a6)
o Fix a locking error in bufferevent_socket_get_dns_error. (0a5eb2e)
o libevent/win32_dealloc() : fix sizeof(pointer) vs sizeof(*pointer)
  (b8f5980 Frank Denis)

BUGFIXES: (other stability)
o bufferevent_pair: don't call downcast(NULL) (f2428a2)
o Consistently check for failure from evbuffer_pullup() (60f8f72)
o Fix race caused by event_active (3c7d6fc vjpai)

BUGFIXES (miscellaneous)
o Avoid redundant invocations of init_extension_functions for IOCP (3b77d62)
o Typo fixes from Linus Nordberg (cec62cb, 8cd695b)
o Add a few files created by "make verify" to .gitignore.
  (1a8295a Pierre Phaneuf)
o regress_buffer: fix 'memcmp' compare size (79800df Maks Naumov)
o Fix bufferevent setwatermark suspend_read (b34e4ac ufo2243)
o Fix evbuffer_peek() with len==-1 and start_at non-NULL. (fb7e76a)

BUFGIXES (evdns)
o Checking request nameserver for NULL, before using it.
  (5c710c0 Belobrov Andrey)
o Fix SEGFAULT after evdns_base_resume if no nameservers installed.
  (f8d7df8 Azat Khuzhin)
o Fix a crash in evdns related to shutting down evdns (9f39c88,e8fe749)

BUGFIXES (epoll)
o Check does arch have the epoll_create and __NR_epoll_wait syscalls.
  (dfe1e52 Marcin Juszkiewicz)

BUGFIXES (evutil_secure_random)
o Avoid other RNG initialization FS reads when urandom file is specified
  (9695e9c, bb52471)
o When we seed from /proc/sys/kernel/random/uuid, count it as success (e35b540)
o Document that arc4random is not a great cryptographic PRNG. (6e49696)
o Add evutil_secure_rng_set_urandom_device_file (2bbb5d7)
o Really remove RNG seeds from the stack (f5ced88)

(bouyer)