Due to leaning towards `musl` builds, unit features for `zstd` and link
it statically too for Zed.
bfe1e34f59/zstd-safe/zstd-sys/build.rs (L260)
shows that `ZSTD_SYS_USE_PKG_CONFIG` env var can be used to return this
behavior.
Release Notes:
- N/A