Build PDF robustly for www.debian.org under Debian stable

Debian's xelatex (or texlive) tends to have major issues with non-English languages to cause PDF build issue.

Currently, languages listed in debian/rules as NOPDF or Makefile as NOPDF build only placeholder PDF files to avoid breaking package building or test PDF building.

So not much more to do after !40 merge on this source tree.

I re-title and keep this issue open until I come up with a setup to upload PDF to www.debian.org page.