Bundling (static linking) TLS library is a very bad idea from the
security perspective and Linux distributions try to avoid it. This
will allow to build xh with native-tls (i.e. dynamically linked
system-provided TLS library) only, without rustls.
We were asking cargo to rebuild if assets/xhs or assets/xhs.1.gz
changed. Those are dead symlinks, so cargo always errors and
[assumes they changed]
(e475fe4a17/src/cargo/core/compiler/fingerprint.rs (L1733)).
That caused a lot of unnecessary rebuilds. I found the problem by
running with `CARGO_LOG=cargo::core::compiler::fingerprint=info`.
Asking cargo to watch only the files we actually care about fixes it.
