sagetex: fix patches
sympow: fix patches
toplevel cleanup
sage-bin: continued
sagenb: postponing; no idea how to workaround #14840
python: add PYTHON{HOME,PATH} to env.d/pythonenv.sh
pari cleanup sq
cephes: patch quickfix
cvxopt: patch quickfix
ecm: patch quickfix
flint: patch quickfix
gap patch quickfix
gdmodule: patch quickfix
ipython: patch quickfix
matplotlib: environment workaround
maxima: environment
python: patch quickfix
scipy patch quickfix
sqlite: patch quickfix
termcap patch quickfix