Starting to backport SP3 to stretch

[Cantor, Scott]

> BTW how much is Xalan useful/required for xml-security-c? I'm stumbling upon
> this because the version of xalan in stretch depends on xerces 3.1, but I'm
> depending on xerces 3.2 from stretch-backports (whose maintainer kindly
> backported for me) and the build ends up using both which obviously blows up.

Obviously Shibboleth doesn't use it (in fact it strongly prefers it *not* be compiled in) but I don't know if that's your question or driving consideration.

-- Scott