This is a known failure, I probably should have put something about that in the release notes, sorry. Basically libxml2 lacks the api functions to make this work. In the latest git I'm using TESTS and XFAIL_TESTS in Makefile.am so this should be clearer.
Possible workaround for this suggested by Daniel Veillard (libxml maintainer):
"Which is why I think the cleanest is to use a custom I/O which will automatically add the DOCTYPE at the beginning of the document, that's the safest and fastest at this point in my opinion."
This is a known failure, I probably should have put something about that in the release notes, sorry. Basically libxml2 lacks the api functions to make this work. In the latest git I'm using TESTS and XFAIL_TESTS in Makefile.am so this should be clearer.
See https://bugzilla.gnome.org/show_bug.cgi?id=169375
Possible workaround for this suggested by Daniel Veillard (libxml maintainer):
"Which is why I think the cleanest is to use a custom I/O which will automatically add the DOCTYPE at the beginning of the document, that's the safest and fastest at this point in my opinion."
http://mail.gnome.org/archives/xml/2011-July/msg00012.html