-y flag for libyosys Python scripts

[donn]

What are the reasons/motivation for this change?

This adds a Python equivalent to the -c option, where scripts importing libyosys can be used.

Most of the requisite work for this was already done to enable Python passes a couple years back, so this is a relatively small changeset, and would add another option for supporting libyosys-based scripts (that does not involve PYTHONPATH shenanigans.)

Explain how this is achieved.

Adding a new opt, -y (-p and -P were already taken,) and running PyRun_SimpleFile on scriptfile. Similar to -c for Tcl, any unprocessed arguments are passed to the script in the form of sys.argv.

If applicable, please suggest to reviewers how they can test the change.

./yosys -y <(echo "
import libyosys as ys

d = ys.Design()
ys.run_pass('help', d)
print(sys.path)
print(sys.argv)") -- test argv

[donn]

Any feedback on this? (The Verific test is failing because of security reasons- I'm a first-time contributor)

[KrystalDelusion]

Any feedback on this? (The Verific test is failing because of security reasons- I'm a first-time contributor)

That should be fixed by #4552, you may need to merge/rebase on latest main to get the fix though

[donn]

Rebased on the wrong upstream for a second there but should be fine now :)

[povik]

Tested here, looks good, though I haven't vetted the usage of the CPython API and the error handling paths around it