Events: fixed warnings with -Wpedantic in epoll notify. Added casts through uintptr_t to suppress "ISO C forbids assignment between function pointer and 'void *'" warnings as seen with -Wpedantic in ngx_epoll_notify() and ngx_epoll_notify_handler(). Additionally, it resolves "assignment type mismatch" warnings as seen with Sun Studio on Linux, "pointer to function... "=" pointer to void" and "pointer to void "=" pointer to function...".