mremap not available under MacOS

> I spoke too soon, I found a replacement rather quickly: realloc
> 
> So the code in the function that uses mremap now reads:
> 
>     //new_address = mremap (buffer->mmap->mmap_area, buffer->mmap- 
> >size,
>                   //buffer->mmap->size + IPOD_MMAP_SIZE, 0);
>     new_address = realloc(buffer->mmap->mmap_area, buffer->mmap->size +
>                           IPOD_MMAP_SIZE);

I wouldn't expect that to do the right thing, ie stuff written to the
realloc'ed zone will probably not end up being written to the on-disk
file. Implementing mremap as a combination of munmap + mmap when it's
not available will probably be much better

Christophe
