[dev env] Devcontainer setup fails on Apple Silicon (`arm64`) because `gcc-multilib` / `g++-multilib` are unavailable

[dotWee]

When creating the devcontainer on M-series Macs (arm64), .devcontainer/install-deps.sh fails during apt-get install because it unconditionally installs gcc-multilib and g++-multilib, which are not available in apt arm64/aarch64 repos.

This blocks devcontainer-based development on Apple Silicon without using Rosetta/emulation.

Environment

• Host: Apple Silicon MacBook (any M-series)

• Container base: Ubuntu (Noble)

• Arch inside container: arm64 / aarch64

  dotwee@macbook ~ % docker run --rm -it ubuntu uname -m
  aarch64

• Devcontainer config: .devcontainer/docker/devcontainer.json

• Bootstrap script: .devcontainer/install-deps.sh

Reproduction

1. Open repo in Dev Containers on an Apple Silicon Mac.
2. Let onCreateCommand run .devcontainer/install-deps.sh.
3. Observe apt failure for multilib packages.

Actual result

Devcontainer creation fails with:

• E: Unable to locate package g++-multilib
• E: Package 'gcc-multilib' has no installation candidate

Log for reference:

...
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package gcc-multilib is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Unable to locate package g++-multilib
E: Couldn't find any package by regex 'g++-multilib'
E: Package 'gcc-multilib' has no installation candidate

Expected result

Well, the devcontainer should initialize successfully on both amd64 and arm64.

Root cause

gcc-multilib and g++-multilib are x86-oriented packages and are not published for Ubuntu arm64 in this setup.