[xml] relax.c changing xmlNode's _private slot

[Petr Pajas <pajas ufal ms mff cuni cz>]

Hi Daniel, All,
while investigating why RelaxNG validation via Perl bindings for libxml2
occasionally result in sigsegv (as reported by Alexei Agafonov on 
perl-xml mail list),
I found the cause to be at relax.c (CVS) around line 9755, where a value 
is assigned to node->_private, while _private is used by Perl bindings 
to store some critical
binding-specific structures (reference counting etc.).  It seems this is 
the only place where
RelaxNG uses _private slot of a xmlNode of the document being validated, 
and it
seems it's only used for some kind of an optimalization. Do you think 
this part could
possibly be rewritten, so that xmlNode's _private slot is preserved 
within RelaxNG validation?

The problematic lines are:
relaxng.c:9755
if (ret == 0) {
 node->_private = define;
}

Thanks,

-- Petr