All there in the title....* signalfd() is a Linux specific api:
SIGNALFD(2):
```
CONFORMING TO top
signalfd() and signalfd4() are Linux-specific.
```
* FreeBSD and OSX and others can use the widely available kevent/kqueue api for a similar effect.
We let the kernel notify us via kevent() [1], okif there is a SIGUSR1 or SIGUSR2, or not. Because arc diff is hard.and then fetch the signal using sigwaitinfo() [2].
[1] https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2
[2] https://www.freebsd.org/cgi/man.cgi?query=sigwaitinfo&sektion=2
I just meant to diff the change to `greeter/authenticator.cpp`, but now that it is all here already, let's just call this a prototype, for someone who knows C/kevent/kqueue to fix.Note: I still have to test this modified version =)