This is a step toward supporting C++ function pointer types, which need
to be
imported and thunked in much the same way as C++ functions, but have a
different
underlying representation. `CalleeFunctionInfo` gives us a way to
abstract
away the representation differences, so expressing import and thunking
in terms
of `CalleeFunctionInfo` lets us reuse that code for function pointers.
Actual support for function pointers will come in a follow-up PR, but
the
API design choices I've made here are driven by that use case.
Geoff Romer
f65572a1e6