Alacritty: Use HPCON definition from winapi

[davidhewitt]

In src/tty/conpty.rs, near the top we have the definition pub type HPCON = *mut c_void;

Once https://github.com/retep998/winapi-rs/pull/699 is released then we can update to a newer winapi and use winapi::um::wincontypes::HPCON;

(I added this definition there so that we could merge the support for ConPty apis without having to depend on a patched winapi.)

[chrisduerr]

The upstream PR has been merged. We will probably still need a new winapi version to be released though.

[davidhewitt]

Yes - I'll watch for a release and submit a PR to close this when I'm aware of a new winapi.

[atouchet]

winapi 0.3.7 is now out.