[Toybox] [PATCH] tar: use same tools for decompression as for compression.

[Rob Landley]

On 4/29/19 5:58 PM, enh via Toybox wrote:
> This is what GNU tar does, so Android's build system jail allows
> bzip2, gzip, and xz, but not bzcat, zcat, and xzcat.

This broke mkroot, at a design level.

I don't plan to implement bzip2 compression side because it's an obsolete
protocol (and because when I did the first half of it years ago the string
sorting heuristics were kind of unintelligible). This means toybox hasn't got
and isn't _going_ to have bzip2, so even though toybox implements bzcat it
toybox tar will never be able to decompress bzip2 archives by itself, because of
android's naming limitation.

It also means that toybox can't decompress gzip files by itself until I finish
gzip compression side (but I intend to write that at some point so I can pass it
through from the host). And that toybox won't be able to decompress xz since I'm
not doing xz compression either, just decompression.

(That's why I was using those names. I'm going through my release checklist for
0.8.1 and I got to the step of using mkroot to build all the target binaries,
and I hit this and went "oh right, todo item fell through the cracks...")

Rob