MAJOR: polling: add event ports support (Solaris)

Event ports are kqueue/epoll polling class for Solaris. Code is based
on https://github.com/joyent/haproxy-1.8/tree/joyent/dev-v1.8.8.
Event ports are available only on SunOS systems derived from
Solaris 10 and later (including illumos systems).
diff --git a/doc/haproxy.1 b/doc/haproxy.1
index 91f58a3..86d17cf 100644
--- a/doc/haproxy.1
+++ b/doc/haproxy.1
@@ -105,6 +105,11 @@
 Disable use of \fBkqueue\fP(2). \fBkqueue\fP(2) is available only on BSD systems.
 
 .TP
+\fB\-dv\fP
+Disable use of event ports. Event ports are available only on SunOS systems
+derived from Solaris 10 and later (including illumos systems).
+
+.TP
 \fB\-ds\fP
 Disable use of speculative \fBepoll\fP(7). \fBepoll\fP(7) is available only on
 Linux 2.6 and some custom Linux 2.4 systems.