* cc-release:
s/OS X/macOS
Additional README updates. [ci skip]
Update CONTRIBUTING.md. [ci skip]
Update README for 0.8.0 release. [ci skip]
removes u3l_log from u3m_bail() and c3_assert()
enable ivory slog printfs during dawn (ethereum pre-boot validation)
removes u3l_log() from critical error-handling code paths
Retarget arvo at v0.8.0.rc.1.
Update solid and brass pills in LFS.
Points arvo submodule at zod.2019.6.3.
removes c3_malloc/free calls from jets
removes unused +mer:in jet
fixes typo in +cue comment
corrects +cue comment
removes incorrect early return in cli argument-parsing
tweaks cue/mug explicit stack conventions once more
uses a separate desk and manual commit for +solid staging (avoids -A)
tweaks explicit stack conventions in +cue jet
refactors explicit stack usage in u3r_mug
* Add cross-compilation for `lmdb`.
* Got built caching working in CI with `cachix`.
* Cache cross compilation dependencies and toolchains.
* Do release builds in CI.
* Upload release builds to `bootstrap.urbit.org` on successful build.
* Lots of optimization work for CI.
* Boot from a solid pill in CI and load arvo with `-A`.
* Increase `vere` HTTP timeout to 15m.
