Support libxml2 2.9.0 and later

[knu]

No description provided.

[knu]

Looking at #829 and https://bugzilla.gnome.org/show_bug.cgi?id=695699 it seems libxml2 2.9.x is completely unusable for us.

I'll add some code to extconf.rb so it won't pick libxml2 2.9.0 or later for build.

[knu]

Well, I mean 2.9.0 and 2.9.1. We'll revisit when libxml2 2.9.2 or whatever comes out.

[knu]

I tested Nokogiri with the current libxml2 master and the number of failures were just two. Seems the position() problem is gone.

[knu]

Just started a libxml2-2.9.1 branch in preparation for the next release of libxml2.

[postmodern]

Looking forward to 2.9.1 support. Noticed nokogiri kept printing a warning about being built against 2.8.0, but loading 2.9.1. Oddly, I do not have libxml 2.8.0 installed on my system.

[flavorjones]

@knu, I'd like to work on this today and tomorrow. Have you made any progress since the Nov 4 commit on that branch? If not, no problem, I just don't want to reproduce work you've already possibly done.

[knu]

@flavorjones Unfortunately not much, so please go ahead and tackle it. I'll be following up whenever I find something. Thanks!

[postmodern]

🎆