Expand description
Centralized build-script logic to support cfg(guest_arch = ...) directives
throughout the HvLite codebase.
By default, cfg(guest_arch = ...) will be the same as Rust built-in
cfg(target_arch = ...), but this can be overwritten by setting the
OPENVMM_GUEST_TARGET=... env var at compile time.
HvLite code should not be written to assume that guest_arch and
target_arch will always be equal!
At some point in the future, HvLite may integrate a full-blown CPU emulator
virt_ backend (akin to what QEMU does), which would allow it to run guest
VMs with a different architecture from the host machine.
e.g: Aarch64 on x86, x86 on Aarch64, or even exotic things, like RISC-V on x86 (assuming someone cares enough to put in the work there + add appropriate CI coverage!).