It seems that Expat does not report declarations
of external parameter entities, even though it reports
the associated parameter entity references.
This patch should enable Expat to call the
external entity ref handler when it encounters
external PE declarations.
I have attached full versions of the modified files
xmlparse.c and xmlrole.c, as well as the corresponding
diffs. The modifications have been made against
xmlrole.c rev. 1.5 and xmlparse.c rev. 1.30.