Only add a symlink to the repository if both the filesystem and
unzip support symlinks. To check the latter, add a ZIP file
containing a symlink, created like this with InfoZIP zip 3.0:
$ echo sample text >textfile
$ ln -s textfile symlink
$ zip -y infozip-symlinks.zip textfile symlink
If we can extract it successfully, we add a symlink to the test
repository for git archive --format=zip, or otherwise skip that
step. Users can see the skipped test and perhaps run it again
with a different unzip version.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>