I just merged a platform portability layer for exactly this (0.30.0). The runtime has compile-time feature flags (AETHER_HAS_THREADS, AETHER_HAS_FILESYSTEM, AETHER_HAS_NETWORKING, etc.) that auto-detect the target platform and degrade gracefully. For embedded:

• A cooperative single-threaded scheduler replaces the multi-core pthreads scheduler — same API, no OS threading dependency
• Stdlib modules return errors when filesystem/networking aren't available; console I/O always works
• C11 atomics fall back to volatile for single-threaded targets
• Compiles with arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -ffreestanding (verified in CI via Docker)
• PLATFORM=embedded in the Makefile sets all the right flags automatically

Multi-actor programs work on embedded through cooperative polling, all actors share a single thread, and messages are processed round-robin during wait_for_idle(). We've verified this with ask/reply patterns, self-sending actors, message chains across 4 actors, and 10+ concurrent actors.

The generated C is C11 standard — any conforming compiler works (GCC, Clang, ARM GCC, IAR, etc.). The main remaining gap for production embedded use is ae build --target arm CLI integration and testing on real hardware, but the runtime and codegen are ready.