The key here would be to replace function execution with module execution and command-line arguments.

So instead of:

  python -c 'from multiprocessing.forkserver import main; main(ARG1, ARG2...)'

you would do:

  python -m multiprocessing.forkserver ARG1 ARG2 ....

Then it should become easy to extract the concatenated command lines.

(and if that works, please do the same for semaphore_tracker ;-))