The -deps target is the wrong target to add this to, since its compile flags
are propagated to both Guest.cpp and Host.cpp. Instead, define the flag only
when processing files within a guest context.
Pointer types inherently cause data layout compatibility issues, so they're
worth special-casing here. The wrappers will type-pun pointers to 32-bit or
64-bit integers (matching the guest architecture) to avoid direct host-side
use of guest pointers without consideration.
Tony Wasserka