Prefer /dev/tty over stdin in terminal functions

[acidghost]

This is part of #500.

[TimonPost]

One quick thing in case you were not aware of this, the tty_fd does not yet use prefer /dev/tty over STDIN.

crossterm/src/event/sys/unix/file_descriptor.rs

Line 67 in 5c12c9c

pub fn tty_fd() -> Result<FileDesc> {

But this is a good thing for now, until the MacOs issue is resolved we should not default it to /dev/tty. However, with this pull request its just a matter of changing the dev/tty at a later stage.

Is that good with you? if so ill merge it.

[acidghost]

Select on macOS supports both stdin and /dev/tty, the isatty should be enough to check which of the two to use.

Anyhow, you can merge it as is and I’ll do some testing when select implementation is in.