* Use BASEFLAGS instead of CFLAGS, and set OPT to something better than "".
This seems to finally make "--enable-optimizations" do some speedup, so
lets use it for 3.9 too now.
* "backported" the 3.10 patch for "largefile" flag in tests, and also the
entire TEST() function from the 3.10.12 recipe, as it makes possible to
run `hp --test python3.9` without hanging (assuming Debugger is set to
kill).
