Build failure with libxml2 2.12

[i0ntempest]

:info:destroot /opt/local/include/libxml2/libxml/valid.h:167:11: error: unknown type name 'xmlElementContentPtr'; did you mean 'xmlElementTablePtr'?
:info:destroot XMLPUBFUN xmlElementContentPtr
:info:destroot           ^~~~~~~~~~~~~~~~~~~~
:info:destroot           xmlElementTablePtr
:info:destroot /opt/local/include/libxml2/libxml/valid.h:115:26: note: 'xmlElementTablePtr' declared here
:info:destroot typedef xmlElementTable *xmlElementTablePtr;
:info:destroot                          ^
:info:destroot /opt/local/include/libxml2/libxml/valid.h:169:7: error: unknown type name 'xmlElementContentType'
:info:destroot                                          xmlElementContentType type);
:info:destroot                                          ^
:info:destroot /opt/local/include/libxml2/libxml/valid.h:170:11: error: unknown type name 'xmlElementContentPtr'; did you mean 'xmlElementTablePtr'?
:info:destroot XMLPUBFUN xmlElementContentPtr
:info:destroot           ^~~~~~~~~~~~~~~~~~~~
:info:destroot           xmlElementTablePtr
:info:destroot /opt/local/include/libxml2/libxml/valid.h:115:26: note: 'xmlElementTablePtr' declared here
:info:destroot typedef xmlElementTable *xmlElementTablePtr;
:info:destroot                          ^
:info:destroot /opt/local/include/libxml2/libxml/valid.h:171:26: error: unknown type name 'xmlElementContentPtr'; did you mean 'xmlElementTablePtr'?
:info:destroot                 xmlCopyElementContent   (xmlElementContentPtr content);
:info:destroot                                          ^~~~~~~~~~~~~~~~~~~~
:info:destroot                                          xmlElementTablePtr
:info:destroot /opt/local/include/libxml2/libxml/valid.h:115:26: note: 'xmlElementTablePtr' declared here
:info:destroot typedef xmlElementTable *xmlElementTablePtr;

Complete log can be found here. Downgrading to 2.11.6 will allow it to build successfully.