Epoll compatibility

EPOLLRDHUP was introduced to kernel 2.6.17, but introduced into glibc headers only later on.
epoll_create1() was introduced to glibc 2.6.27, but can be implemented using the older epoll_create().

This fix makes compilation possible and working as expected on older kernels (and glibc), provided you have at least kernel 2.6.17.
  
I'm running kernel 2.6.18 and glibc 2.5 (RedHat 5.2).