Automatic forward declarations?

[rversteegen]

Currently, fbfrog ignores forward struct declarations by default, if no definition of the struct appears later:

struct Typ;
extern Typ *x;

translates to

extern x as Typ ptr

whereas if struct Typ {int a;}; appears later you get

type Typ as Typ_
extern x as Typ ptr

type Typ_
	a as long
end type

Without the definition, adding -addforwarddecl Type is necessary to get a working translation.

Why not add a forward declaration automatically if there is a C declaration but no definition; is it not desirable for some reason, or is it simply not implemented? The only reason to avoid doing so that I can think of is if there's another header that fbfrog wasn't given which will have already defined it. But that would be the exception, not the norm, accommodated with a -noforwarddecl option.