Firmware now builds in a VSCode "Remote Container"

.devcontainer/Dockerfile

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+# See here for image contents: https://github.com/microsoft/vscode-dev-containers/blob/v0.241.1/containers/debian/.devcontainer/base.Dockerfile
+
+# [Choice] Debian version (use bullseye on local arm64/Apple Silicon): bullseye, buster
+ARG VARIANT=bullseye
+FROM mcr.microsoft.com/vscode/devcontainers/base:${VARIANT}
+
+RUN    apt update \
+    && apt upgrade -y \
+    && apt install -y \
+        build-essential git wget binfmt-support qemu gcc-9 \
+        parted gcc-avr avr-libc avrdude python3 python3-tornado curl \
+        unzip python3-setuptools gcc-arm-linux-gnueabihf bc sudo \
+    && update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 9 \
+    && curl -fsSL https://deb.nodesource.com/setup_18.x | bash - \
+    && apt install -y nodejs

.devcontainer/devcontainer.json

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+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/blob/v0.241.1/containers/debian
+{
+	"name": "Debian",
+	"build": {
+		"dockerfile": "Dockerfile",
+		// Update 'VARIANT' to pick an Debian version: bullseye, buster
+		// Use bullseye on local arm64/Apple Silicon.
+		"args": { "VARIANT": "bullseye" }
+	},
+
+	"runArgs": ["--privileged"],
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [],
+
+	// Uncomment to use the Docker CLI from inside the container. See https://aka.ms/vscode-remote/samples/docker-from-docker.
+	// "mounts": [ "source=/var/run/docker.sock,target=/var/run/docker.sock,type=bind" ],
+
+	// Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+	// "remoteUser": "vscode",
+	
+	"features": {
+		"sshd": "latest"
+	}
+}