sys/event.h's kevent.udata and c++

For src/sys/sys/event.h

I am told that kevent.udata should maybe be void * since C++ doesn't 
allow the naive conversion from a pointer type to integer. Apparently 
some other systems have that has void *.

Before I change I get errors like:

../../../ext/asio/asio/detail/kqueue_reactor.hpp: In member function 
'void asio::detail::kqueue_reactor::start_op(int, 
asio::detail::socket_type, 
asio::detail::kqueue_reactor::descriptor_state*&, 
asio::detail::reactor_op*, bool)':
../../../ext/asio/asio/detail/kqueue_reactor.hpp:180: error: invalid 
conversion from 'asio::detail::kqueue_reactor::descriptor_state*' to 
'__intptr_t'

Okay to change that?