WITHOUT_BZIP2_SUPPORT only affects a single binary, gzip(1); it doesn't
remove bzip2 support from other bits (e.g., libarchive) and there are
no similar options for gzip, xz or zstd.
WITHOUT_BZIP2 has not done anything at all since it was first added
in 2007.
MFC after: never
Discussed on: arch@
Sponsored by: https://www.patreon.com/bsdivy