Comment 1 for bug 899066

Do you mean "python-xml" or "python-lxml"? The first is likely to be a dead package containing "PyXML". You don't need that.

Regarding the "ASCII" encoding - it seems that the best name for CPython to see is "ascii", in lower case. libxml2 prefers the upper case names, that's why Ixml had used those internally. Normally, CPython also gets along with the upper case names nicely, so I wonder what the problem is on your side. Maybe some Archlinux specifc issue?

I pushed a fix here:

https://github.com/lxml/lxml/commit/90b0b10743b89ec4e0533a9ebca42715f0054366

If you want to try it, you need Cython 0.15 to build from sources.