tree 5119f17df880cbbe1a3cd28b33e1c659e94dcaf3
parent 8902d2fabad581d42c7d5e64c5b29c91ffe58d43
author Joanmarie Diggs <jdiggs@igalia.com> 1623234380 +0200
committer Michael[tm] Smith <mike@w3.org> 1623236490 +0900

conformance-checkers: Use Python 3 in Makefile; don't override envars

Makefile uses the --sort-keys command line option which was introduced
in Python 3.5. Setting PYTHON to "python" means make will fail in
environments where Python 2 is the default. Furthermore, setting it
unconditionally means that users cannot work around this in their own
environment.

Set PYTHON to "python3" and also replace the = operator with ?= so that
variables are only set by Makefile when not already set locally. (Thanks
gsnedders for the operator tip!)

Fixes #29196.