wheels: bison 3.8 on almalinux + memory pressure easing

- cibw now builds and uses bison 3.8.2 explicitly on platforms with no or out-of-date bison — AlmaLinux 8 only goes up to Bison 3.0
- cibw environment now includes `OPTFLAGS=-O3` to avoid generating debug info for abc, saving space in memory during linking
- setup.py attempts to build `yosys-abc` independently first to avoid memory pressure from gigantic abc link step running in parallel with something else

.gitignore

@@ -47,6 +47,7 @@
 /kernel/python_wrappers.cc
 /boost
 /ffi
+/bison
 /venv
 /*.whl
 /*.egg-info