[xml] Localizing the validation messages

[Patrick <patrick hapax qc ca>]

Our technical customers do not want to see English messages when the 
documents they tag do not conform to the XSD schema defined. The tool 
uses lxml which I understand is a pythonic binding to libxml2.

They want the XML validation messages in their language.

So, not

Element 'b': Element content is not allowed, because the type definition 
is simple.

but, for instance,

Élément 'b' : Pas de contenu d'élément permis, parce que la définition 
de type est simple.
Elemento 'b': Elemento de contenido no está permitido, ya que la 
definición de tipo es simple.

I believe localization of libxml2 has not been implemented, is that 
still true? How hard would it be to do?

P. A.