first commit

builder/debian/install-cross.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+set -euo pipefail
+
+if [[ ${EUID} -ne 0 ]]; then
+    echo "Run as root" >&2
+    exit 1
+fi
+
+apt-get update
+DEBIAN_FRONTEND=noninteractive apt-get install -y docker.io rustup build-essential pkg-config
+systemctl enable --now docker
+
+TARGET_USER="${SUDO_USER:-root}"
+if [[ "$TARGET_USER" == "root" ]]; then
+    rustup default stable
+    cargo install cross --locked
+else
+    sudo -u "$TARGET_USER" -H sh -c 'rustup default stable && cargo install cross --locked'
+fi
+
+echo "Docker + rustup + cross installed for $TARGET_USER."
+echo "Use BUILD_MODE=cross-binary only for development validation."