This firstly means that Makefile variables such as `PYTHON' are honoured
properly, and secondly that flags requesting parallel building are
respected.
rm -rf _distcheck
$(PYTHON) setup.py sdist --dist-dir _distcheck
cd _distcheck && tar xvfz $(distdir).tar.gz
- cd _distcheck/$(distdir) && make && make check && make dist
+ cd _distcheck/$(distdir) && $(MAKE) && $(MAKE) check && $(MAKE) dist
cp _distcheck/$(distdir)/$(distdir).tar.gz .
rm -rf _distcheck