Implement epoll support in Linuxulator. This is a tiny wrapper around kqueue
to implement epoll subset of functionality. The kqueue user data are 32bit
on i386 which is not enough for epoll user data so this patch overrides
kqueue fileops to maintain enough space in struct file.

Initial patch developed by me in 2007 and then extended and finished
by Yuri Victorovich.

Approved by:    re (delphij)
Sponsored by:   Google Summer of Code
Submitted by:   Yuri Victorovich <yuri at rawbw dot com>
Tested by:      Yuri Victorovich <yuri at rawbw dot com>
Regen.

Approved by:    re (delphij)