Better fix for case of excluded symlinks that point nowhere when using

Better fix for case of excluded symlinks that point nowhere when using
--copy-links.  The readlink_stat() does need to be done in the normal case
before checking the exclude patterns because it needs to know whether or
not a file is a directory in order to properly handle a trailing slash
in an exclude pattern.  This fix makes make_file() go ahead and call
readlink_stat() but then if the latter returns an ENOENT and copy_links is
on then it will only print an error if the path is not excluded.