New comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/46117#issuecomment-1727894679

Comment:
Alright, it turns out that meson respects `$CFLAGS`, `$LDFLAGS` and `$CXXFLAGS` in the environment at configure time, so we don't need to write them to the cross file; leaving these out produces a valid cross file and lets us customize the flags in templates before `do_configure` is run.

As for re-using `do_configure`, this might not be necessary for the few packages that will be moving to `mesonpy` PEP517 builds in the future, so I'm going to ignore it now.

I've updated `python3-scipy` to use the new helper in conjunction with the `python3-pep517` build style, and will be rebuilding all of the packages with `build_style=meson` to confirm that this doesn't break anything.