More libxml2 work-arounds.
More libxml2 work-arounds.

marclaporte/WeasyPrint,prepare/TestWeasyPrint,Kozea/WeasyPrint,andrewleech/WeasyPrint,andrewleech/WeasyPrint,jasco/WeasyPrint,prepare/TestWeasyPrint,marclaporte/WeasyPrint,jasco/WeasyPrint,Kozea/WeasyPrint