zstd

To import new vendor sources, prune unwanted files with:

	tar -X FREEBSD-Xlist -xf zstd-x.y.z.tar.zst

When importing a new version, be sure to check if there are any new bits that
we don't want.

Please find instructions for importing new releases and merging to HEAD here:

https://docs.freebsd.org/en/articles/committers-guide/#vendor-import-git