When restoring a tar file using smbclient a core dump occurs when
there are long file names (ie: >= 100 length names, using the
@LongLink dummy record convention).

When encountering the "/./@LongLink" header, get_longfilename() is
called.  But it allocates space using strlen(finfo.name), which
at this point is "././@LongLink" or similar, rather than finfo.size,
which is the real length of the long file name.

The attached patch replaces strlen(finfo.name) with finfo.size.  In fact,
the code was this way in 2.2.3 (haven't checked later 2.2.x releases).