add arm64 prebuilds for alpine

[Chicken]

Arm64 is getting more and more popular with the oracle servers and raspberry pi's so it would be great to have prebuilds for it.
Could have probably added arm64 support for other builds too but didn't want to start testing if they actually work.

[mceachen]

I ran this locally and rebuild ignored the --arch flag and produced x64 binaries.

How'd you test this?

[Chicken]

I ran all the commands in a docker environment like the workflow would do:
docker run --rm -it --entrypoint /bin/sh node:16-alpine
and then
apk add build-base git python3 --update-cache
git clone https://github.com/JoshuaWise/better-sqlite3
cd better-sqlite3
npm install --ignore-scripts
npx --no-install prebuild -r node -t 10.20.0 -t 12.0.0 -t 14.0.0 -t 16.0.0 --include-regex 'better_sqlite3.node$' --arch aarch64
The --arch flag is for sure the correct one. It's even used in the windows build as --arch ia32
And the output sure looks correct to me:

[mceachen]

Thanks for providing the commands you used!

And the output sure looks correct to me:

The tarball, at least on my box, is correctly named, but has incorrect binaries:

/better-sqlite3/prebuilds # ls
better-sqlite3-v7.4.4-node-v64-linuxmusl-aarch64.tar.gz
/better-sqlite3/prebuilds # tar xvzf better-sqlite3-v7.4.4-node-v64-linuxmusl-aarch64.tar.gz 
build/Release/better_sqlite3.node
/better-sqlite3/prebuilds # file build/Release/better_sqlite3.node 
build/Release/better_sqlite3.node: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, with debug_info, not stripped

To build cross-architecture binaries, I'd expect QEMU (or something like it) to come into play at some point, and I don't see prebuild using that.

TBH, I'm a prebuild n00b: do you know of other projects building cross-architecture prebuilds so we can crib from their work?

[Chicken]

That's certainly interesting...
I sadly don't know any other projects that do this and I'm not sure how hard it would be to find one.
I was basing everything on these four facts:

• normally builds and runs fine
• the windows build uses the arch flag
• prebuild accepts the flag, does something with it, and doesn't complain
• the tarballs are correctly named

I'll look into this more

[Chicken]

Alright, I no longer have any idea what is happening and why. I'll later try to make a workflow which emulates arm64 with qemu and docker to run the prebuilds. No guarantees if that works though as github workflows are really hard to test.
Honestly kinda annoyed at prebuild. That's some stupid behavior and probably a bug...

[Chicken]

Ran a test with it:
(though the test used a slighty modified version defined here)
https://github.com/Chicken/better-sqlite3/runs/4249357964

Now it properly works!

[JoshuaWise]

LGTM