ExtUtils::Constant::WriteConstants (
    NAME => 'Foo::Bar',
    NAMES => [ qw(EPOLLIN EPOLLOUT) ]
);

##</code><code>##

#include "const-c.inc"
#include <sys/epoll.h>  // hail mary...

MODULE = Foo::Bar    PACKAGE = Foo::Bar
INCLUDE: const-xs.inc

##</code><code>##

is(Foo::Bar::EPOLLOUT, 4);