creating debuginfo manually [slightly offtopic]

I was debugging some reverse engineering challenges and wondered: is
it possible to define debuginfo semi-manually?

Let's say I have a stripped binary but I already learned that there is
an array of structs at location 0x0804abcd.
I would like to teach that also to gdb, probably via symbol-file.  (Or?)

I was thinking how to create this debuginfo file.  I came up with this ugly way:

$ cat dummy.c
struct chunkdesc {
    void *offset;
    unsigned int len;
};

struct chunkdesc chunks[3];
void main() {}
$ cc -m32 -g -O0 -Wl,--defsym=chunks=0x0804abcd dummy.c -o dummy.elf

and use "symbol-file dummy.elf" in gdb.  This seems to work for this
case, but I cannot define function prototypes this way.

Is there any better way to do this?