Initial implementation of FFI macro and codegen tool#1

Merged

Manishearth merged 6 commits intorust-diplomat:mainfrom shadaj:initial-extern-c

Jun 22, 2021

+793

Commits on Jun 17, 2021

Initial macro for generating extern C functions
shadaj
committed

Commits on Jun 18, 2021

Commits on Jun 21, 2021

Commits on Jun 22, 2021

Restore logic for adding repr(C) to structs
shadaj
committed