Build ARM docker image in GitHub Actions using QEMU (#400)

This PR updates the GH Action docker workflow to crossbuild the docker
image for ARM using QEMU.
This theoratically works but takes about for a clean build 2.5 hours,
which may or may not be tolerable for each commit on `main`.
A action run where the dependencies are already cached needs about 15
minutes with this PR.

1 files changed, 4 insertions, 0 deletions

diff --git a/Dockerfile b/Dockerfile
index c34ba40f..408d3992 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,6 +6,10 @@ COPY . .
 RUN cargo chef prepare --recipe-path recipe.json
 
 FROM chef AS builder
+
+# Ensure working C compile setup (not installed by default in arm64 images)
+RUN apt update && apt install build-essential -y
+
 COPY --from=planner /app/recipe.json recipe.json
 RUN cargo chef cook --release --recipe-path recipe.json