xdv-lib is the target/runtime library for XDV-specific boot and kernel
services.
Design goal:
- Keep the Dust compiler target-agnostic and GCC-style object compatible.
- Put XDV boot/runtime behavior in a linkable library instead of compiler hardcoding.
This library defines K-regime APIs that XDV components can call. The compiler should only compile and link calls; it should not embed any XDV-specific runtime logic.