The updater itself does not link to NSS on Windows and instead uses the
Windows-internal crypto libraries. However the mar executable needs to
link against NSS, so we need to split the code a bit.

Change-Id: Iea61c716aa507a876fdb444eb28ad828bdea18bd
Reviewed-on: https://gerrit.libreoffice.org/40608Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>