Unable to build contrib.lua with pthread support

[mrnickzh]

Trying to link contrib.lua with my project, that has --pthread enabled, build errors out with wasm-ld: error: --shared-memory is disallowed by ldo.c.o because it was not compiled with 'atomics' or 'bulk-memory' features.
Couldnt find any way to build lua with pthread support using embuilder, kinda stuck on this issue for now

[sbc100]

We would need to add an -mt variant to the lua build. See sdl2.py for an example of how to do this. Would you be able to send a PR for this?

[mrnickzh]

Im not sure if lua supports pthreads, because its natively single-threaded.

[mrnickzh]

ok i made some changes to the script and it worked, but im really, really bad at programming, so idk if i can make a proper PR

[sbc100]

lua.c does seem to contains some kind of atomics at least because otherwise you wouldn't see the it was not compiled with 'atomics' or 'bulk-memory' features error. That only shows up for object files that have such features and they get lowered away.

[sbc100]

Thanks for the PR. I'm sure we can make it work, and I can alwasys update it if needs be.