TODO: document portability requirements for atomic pointer access
TODO: document requirements for function pointers and calling conventions.
+ - move some declarations at the beginning to help certain retarded
+ microsoft compilers, even though their documentation claims
+ otherwise (reported by Ruslan Osmanov).
+
4.22 Sun Dec 20 22:11:50 CET 2015
- when epoll detects unremovable fds in the fd set, rebuild
only the epoll descriptor, not the signal pipe, to avoid