As per https://peps.python.org/pep-0394/, the python binary can be one
of the following options:
- Python 2
- Python 3
- Not exist
All of the scripts in libxml2 use 'python', which may not exist.
As Python 2 reached EOL on the 1st January 2020, it's safe to move the
scripts to use python3 explicitly.
* schematron.c xpath.c: applied a couple of patches from Martin
avoiding some leaks, fixinq QName checks in XPath, XPath debugging
and schematron code cleanups.
* python/tests/Makefile.am python/tests/xpathleak.py: add the
specific regression tests, just tweak it to avoid output by default
Daniel
svn path=/trunk/; revision=3791