If unknown structs show up in functions or fields (as a pointer), define them now so the D file can compile See it.c.compile.delayed.
Remember this aggregate cursor
In C it's possible for a struct field name to have the same name as a struct because of elaborated names. We remember them here in case we need to fix them.
Tells the context to remember a struct type encountered in an aggregate field. Typically this will be a pointer to a structure but it could also be the return type or parameter types of a function pointer field.
return the spelling if it exists, or our made-up nickname for it if not
Command-line options
Context for the current translation, to avoid global variables