* bpo-30947: Update libexpat from 2.2.1 to 2.2.3

* Add NEWS entry

* Add new loadlibrary.c

* expat_external.h: restore include "pyexpatns.h"

* PCbuild: add expat/loadlibrary.c

* Define XML_POOR_ENTROPY to compile expat

Python 2.7 backport: add expat/loadlibrary.c to PC/VS9.0/ project
files (_elementtree and pyexpat).

(cherry picked from commit 93d0cb58)