Toward removing robotlocomotion/director tap

[svenevs]

VTK and clang-format are the only things that come from https://github.com/RobotLocomotion/homebrew-director

$ grep -ri robot setup/mac/
setup/mac/binary_distribution/Brewfile:4:tap 'robotlocomotion/director'
setup/mac/binary_distribution/Brewfile:27:brew 'robotlocomotion/director/[email protected]'
setup/mac/source_distribution/Brewfile:4:tap 'robotlocomotion/director'
setup/mac/source_distribution/Brewfile:7:brew 'robotlocomotion/director/clang-format@12'

• Remove vtk (via Link VTK privately #16502 and tarball downloads rather than brew installs)
• Make a decision on what to do about clang-format@12 formula

When building locally using brew install -v --build-from-source ./[email protected], downloading and staging take a bit, and there are (at least with clang 12) 795 objects being compiled. AFAICT this gets compiled in serial

• mac mini arm64: ~2 minutes 12 seconds.
• older x86 mac: ~6 minutes 6 seconds.

Seems possibly reasonable to incorporate this into drake's workspace if we so desired. Then again, this is notably a lot more time than just downloading our precompiled bottle. There aren't many dependencies for the formula, and as a result we rarely need to rebottle it (haven't needed to since we switched to 12 and did the first one).

CC @BetsyMcPhail @jwnimmer-tri

[jwnimmer-tri]

LLVM does have BUILD files now. I have a WIP here where I started trying it. I don't remember what (if any) roadblocks I hit.

[jwnimmer-tri]

Also another WIP here is relevant. Both should probably happen together.

[jwnimmer-tri]

Fixed in #21339.