cfg(unix) is so broad (comparing to
cfg(windows), for example) that it's often not very useful.
I think it would make sense to group the Unix systems as Apple variants, BSD variants, Linux, and the rest.
Check this rwh code for example:
#[cfg_attr( not(feature = "nightly-docs"), cfg(any( target_os = "linux", target_os = "dragonfly", target_os = "freebsd", target_os = "netbsd", target_os = "openbsd" )) )]
Enumerating all the BSD systems is something that's likely needed for any crate that can't mix up all the Unix systems. So it would be very useful to be able to say
cfg(any(target_os = "linux", unix-bsd)).
Similarly, we have many places in the gfx-rs related code where we differentiate between Apple's Unix versus other unixes. It would be great to be able to say
Any concerns about having these configuration shortcuts defined?