Reallocates the memory pointed to by @mem, so that it now has space for
@n_bytes bytes of memory. It returns the new address of the memory, which may
have been moved. @mem may be %NULL, in which case it's considered to
have zero-length. @n_bytes may be 0, in which case %NULL will be returned
and @mem will be freed unless it is %NULL.
Reallocates the memory pointed to by @mem, so that it now has space for @n_bytes bytes of memory. It returns the new address of the memory, which may have been moved. @mem may be %NULL, in which case it's considered to have zero-length. @n_bytes may be 0, in which case %NULL will be returned and @mem will be freed unless it is %NULL.