run-make-check.sh ccache tweaks
Erwan Velu implemented some nice ccache tweaks for run-make-check.sh which reportedly bring a substantial performance improvement. Anything that makes "make check" easier to run would seem like a good thing, so I proposed opening up those tweaks to all users of the script. Erwan also suggested to backport the tweaks to mimic and luminous.
Master PRs to backport: