- drop libxml2-freebsd.patch.1 (upstream libtool 2.4.6 does the same)
- drop libxml2-vc15.patch (fixed upstream)

Change-Id: Ia2f194f39efebd3d2ea924d23a5543ac53e93116
Reviewed-on: https://gerrit.libreoffice.org/20084Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>
(cherry picked from commit 391bcf34)
Reviewed-on: https://gerrit.libreoffice.org/20095Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>