Handle more corner cases in sys/event.h for C++ EV_SET()

Handle the udata argument as Plain-Old-Data types separately.

- int, long int, long long int
- unsigned int, unsigned long int, unsigned long long int
- void *

This approach handles each of the POD types separately on purpose as
intermediate types such as intptr_t can be either int or long (even long
long) and handling them is not portable.

This approach is compatibile with C++98 and newer.

Fixes i386 usage.

(kamil)