As of revision 0015a25415455c390ae135bef7de2d5e2b10ee88:

$ cat test.go
// +build ignore

package test

/*
typedef struct {
        void *p;
        void **q;
        void ***r;
} s;
*/
import "C"

type S C.s

$ go tool cgo -cdefs test.go
// Created by cgo -cdefs - DO NOT EDIT
// cgo -cdefs test.go


typedef struct S S;

#pragma pack on

struct S {
        byte    *p;
        byte    **q;
        void    ***r;
};


#pragma pack off

$ go tool cgo -godefs test.go
// Created by cgo -godefs - DO NOT EDIT
// cgo -godefs test.go

package test

type S struct {
        P       *byte
        Q       **byte
        R       **unsafe.Pointer
}


At a minimum, this seems inconsistent to me, and we can simplify cmd/cgo somewhat
(namely eliminating typeConv.todoFlds) if we're okay with simply always mapping
"void *" to "*byte".  I've looked over the uses of -cdefs and
-godefs in the runtime and syscall packages, and I don't see any types that should
change as a consequence of this.