Pass strict validation

The patch does eliminate the strict validation errors.
On my 12.04 server I get 11610 of these (both before and after the patch):

Unimplemented block at ../../relaxng.c:9024

I'll try again on my 14.04 VM and with the upstream yelp-tools and yelp-xsl once I get it working.
I'm going to commit this in the meantime.

On my 14.04 Desktop VM, using the upstream yelp-tools and yelp-xsl (or so I believe), I still get several thousand

Unimplemented block at ../../relaxng.c:9054

lines printed. Lines spewing at such a high rate can potentially mask real issues.

My fault. I forgot that the --allow option requires a fix I did on libxml2, which appears to not be in any released version yet. I'll ping the libxml2 maintainer about getting a release out.

The patch is still fine. You just can't do the bestest in Mallard validation without building libxml2 from git master. You can use --strict without any --allow options, but it'll complain about any pages where you're using ITS or experimental features. You can also use yelp-check validate without --strict. It just might not report errors in how you've used things like conditionals or UI expanders.

Thanks for the information. As a temporary solution, I'm doing this:

yelp-check validate --strict --allow http://www.w3.org/2005/11/its --allow http://www.w3.org/1999/xlink --allow http://projectmallard.org/experimental/ *.page | grep -v "relaxng\.c"

And, ugh oh, a validation error was introduce in the latest, and already accepted, Merge Proposal.