Rust Cross

This covers the practical side of cross-compiling Rust: rustup targets, the cross tool for Docker-based builds, and cargo-zigbuild for zero-setup compilation via zig cc. It's useful when you need to build for ARM on x86, create static musl binaries, or target embedded bare-metal systems. The workflow is concrete, with target triples for common platforms like aarch64 Linux, Windows, macOS, and Cortex-M microcontrollers. Cross and cargo-zigbuild are both solid choices, but zigbuild wins on speed and simplicity if you don't need Docker isolation. The embedded section shows the no_std setup with memory.x linker scripts and probe-run for actual hardware.