Replace external deps with homebrew formulae

[equal-l2]

Current external deps and why can't replace with homebrew formula now

• luv - No formula yet
• luajit - Homebrew luajit can't build neovim-bundled luarocks
• luarocks - Homebrew luajit doesn't bundle luarocks, and luarocks formula doesn't exist

[justinmk]

luajit can't build neovim-bundled luarocks

We can remove luarocks dep.

[equal-l2]

@justinmk
I'm afraid it's not true.
If you remove luarocks, neovim install script cannot find lua, complaining
The 'lpeg' lua package is required for building Neovim.

[justinmk]

Ah, right.

[javian]

luarocks exists in the homebrew boneyard and it was re/moved here Homebrew/legacy-homebrew#37842 so it looks like any project that uses need to bundle it in the way its done now.

[equal-l2]

Building bundled luarocks with homebrew luajit needs a patch so that configure can find luajit's lua.h correctly.

In detail, we need pass --with-lua-include=`brew --prefix luajit`/include/luajit-2.0 to luarocks' configure.

[equal-l2]

Maybe we should go with current method with these 3 deps, instead of making difficult workarounds.

Homebrew seems not to work well with luajit.

[justinmk]

@equal-l2 Agreed. At some point we will ship lua and the few lua-based dependencies "statically" as part of nvim core--similar to how the VimL runtime files are shipped. Then these homebrew-visible dependencies won't be needed. Update: in neovim/neovim#4411 we don't "inline" lua, we still require lua or luajit as dependencies.

[equal-l2]

Then we will wait until the time comes.