[Aboriginal] Refactoring/recycling

[Rob Landley]

I've been breaking aboriginal linux down for parts. It's just too much
of a giant hairball, despite my attempts to separate it into layers.

The thing is, once you take out the toolchain build (and replace it with
Rich Felker's musl-cross-make), there's only 5 other packages it builds
(toybox, busybox, make, bash, distcc). All of them compile reasonably
easily, and as toybox adances at least 2 of them should go away. The
infrastructure aboriginal linux provides for them is WAY OVERKILL for
what's left for it to do (as evidenced by
https:/github.com/j-core.org/mkroot working fine without any of it).

What Aboriginal Linux has is:

1) The ./download.sh infrastructure to download and patch source code,
and maintain an extracted "package cache" for parallel builds. This
includes setup and teardown wrappers to _use_ the package cache (and set
up the cross compiler path, and so on).

2) The host-tools.sh "airlock step" and environment sanitization logic
(sources/variables.sh) for doing "hermetic builds" (I.E.
portable/reproducible builds that provide their own known build
environment).

3) target configs with matching gcc tuple (and flags), kernel config
(and KARCH), and qemu command line (and kernel command line).

4) Wrapper script to launch qemu with some infrastucture around it (most
of which supports build control images; note that
http://landley.net/aboriginal/build-control to _create_ build control
images is a separate project with its own git repo).

5) Busybox and uClibc config files (now legacy info).

6) A dozen package build recipes (in sources/sections), 2/3 which
(ccwrap.sh, gcc.sh, musl.build, uClibc.build, binutils.build,
linux-headers.sh, uClibc++.build, elf2flt.sh) are obsolete if we use
Rich's toolchain instead of building our own.

7) The miniconfig.sh stuff

8) record-commands.sh

I'm still reading through my old stuff, but that seems to be the bulk of it.

If you move to musl-cross-make and mkroot.sh, #5 and #6 can pretty much
be abandoned. I can extend mkroot.sh to (optionally) build make and
distcc for a target, neither is a big deal. I need to get serious about
toybox's built-in shell.

I can break out #1 into its own project. I hadn't yet because it seems
like overkill: mkroot doesn't do it and hasn't needed it? Still, Jeff
was hitting the lack of this one last week...

I'm already porting #2 (the host-tools.sh stuff) into the toybox build.
Maybe there should be a "scripts/hermetic.sh" to set up a hermetic build
environment, maybe it should be an install target, not sure yet. (It's
not _just_ an install, there's a chroot-like step to change the $PATH
and unset all unrecognized environment variables checking the
whitelist...) The record-commands.sh stuff should should go in there
too, it's separate but related.

I should throw miniconfig at the kernel again and see if it sticks. (It
won't, but as far as I'm concerned reposting it with explanation
annually is probably good enough.)

That leaves #3 and #4 which I can maybe wrap up together as their own
thing? Haven't decided about that bit yet. Maybe it belongs alongside
mkroot?

Rob