CTFE with C functions not possible?

[Rikki Cattermole via Digitalmars-d-learn]

On 01/01/16 11:15 PM, Shriramana Sharma wrote:
> Rikki Cattermole wrote:
>
>> Either port it to D and extern(C) it so it is accesible from other
>> languages or not have CTFE support.
>
> I already wrote it in D, then I ported to C with much effort. The option to
> extern(C)-ing it didn't occur to me. :-( Also, the D version is really much
> too bulky.
>
> I suppose I could always maintain both the C and D versions separately.

How exactly is a D version more bulky then C?
After all everything C can do, D can do with a very similar syntax.