Read the release cookie from the environment

[pepicrft]

This PR attempts to fix this issue.

I noticed the RELEASE_COOKIE variable passed to the binary generated by Burrito did not get forwarded to the underlying Erlang runtime. After diving into the code, I noticed that the logic that runs ERTS reads the cookie from a file and then passes it as an argument when shelling out.

I'm not familiar with Zig, so bear with me. The code below doesn't work, but I thought I'd push it to kick some discussions and get some pointers to push this to a finish line.

[pepicrft]

@doawoo I'd appreciate your support in this one :)

[doawoo]

Heyo!

I'll take a look at this soon. So to clarify your use case, you just want the underlying RELEASE_COOKIE env variable to be passed down into the erlang process when launched? Instead of the file?

[pepicrft]

I'll take a look at this soon. So to clarify your use case, you just want the underlying RELEASE_COOKIE env variable to be passed down into the erlang process when launched? Instead of the file?

That's correct! Such that anyone can launch the Burrito-generated portable binary passing that variable at runtime:

RELEASE_COOKIE=foo ./burrito_binary

Thanks a lot @doawoo 🙏🏼. I appreciate that you'll look into this.

[doawoo]

Ok I have a solution for this incoming! Your code helped kick this off, so thanks! Going to close this specific PR for now though.