I wanted to share my experience in trying to improve rust-bitcoin crate build times.
I noticed secp256k1-sys native build script was taking a significant amount of time

And I noticed cc wasn't using the parallel feature, so I enabled it. This successfully shaved a second from secp256k1-sys build time, however, the overall build time is worst because now cc has now to wait libc to start building.

I wonder if it's possible for jobserver to avoid to depend on libc