lang/s7: update to 11.2.g20241217

• convert to SETENVI
• ship more documentation
• pass -fno-math-errno as per instructions in s7.c
• try to get the test suite working; unfortunately it hard codes the assumption that HOME=/home/${USER}, which we cannot support; author is informed

Changelog: https://cm-gitlab.stanford.edu/bil/s7/-/commits/master/?ref_type=HEADS