Passing ADDITIONAL_GUIX_COMMON_FLAGS="--no-substitutes --bootstrap" as
suggested doesn't work:
```bash
...outputting in: '/bitcoin/guix-build-a1f0b8b62eb8/output/x86_64-linux-gnu'
...bind-mounted in container to: '/outdir-base/x86_64-linux-gnu'
guix time-machine: error: bootstrap: unrecognized option
```
and I think bootstrapping is more than covered in the preceding "Choose
your security model" section.
In Guix, there are two flags for controlling parallelism:
Note: When I say "derivation," think "package"
--cores=n
- controls the number of CPU cores to build each derivation. This is
the value passed to `make`'s `--jobs=` flag.
- defaults to 0: as many cores as is available
--max-jobs=n
- controls how many derivations can be built in parallel
- defaults to 1
Therefore, if set --max-jobs=$MAX_JOBS and don't set --cores, Guix could
theoretically spin up $MAX_JOBS * $(nproc) number of threads, and that's
no good.
So we could either default to --cores=1, --max-jobs=$MAX_JOBS
- Pro: --cores=1 means that `make` will be invoked with `-j1`,
avoiding problems with package whose build systems and test
suites break when running multi-threaded.
- Con: There will be times when only 1 or 2 derivations can be built
at a time, because the rest of the dependency graph all depend
on those 1 or 2 derivations. During these times, the machine
will be severely under-utilized.
or --cores=$MAX_JOBS, --max-jobs=1
- Pro: We don't encounter prolonged periods of
severe under-utilization mentioned above.
- Con: Many packages' build systems and test suites break when running
multi-threaded.
or --cores=1, --max-jobs=1 and let the user override with
$ADDITIONAL_GUIX_COMMON_FLAGS
- Clearer and more accurate prose
- Pin `guix pull' to commit rather than branch
- Just use `use-module' instead of `define-module'
- Use `bash-minimal' instead of `bash'
- Remove unneeded `tcsh' from manifest
- Explicitly use `python-3.7'
- Add comments about how {native,cross}-toolchains are produced and
why
