Moving FStar.Getopt -> FStarC.Getopt

[mtzguido]

Hi Tahina, this is needed after F* PR FStarLang/FStar#3557

[mtzguido]

2024-10-11T08:36:27.6849936Z   DUNE BUILD
2024-10-11T08:36:28.0117184Z File "dune-project", line 1, characters 11-14:
2024-10-11T08:36:28.0119101Z 1 | (lang dune 3.8)
2024-10-11T08:36:28.0120111Z                ^^^
2024-10-11T08:36:28.0121548Z Error: Version 3.8 of the dune language is not supported.
2024-10-11T08:36:28.0124370Z Supported versions of this extension in version 3.8 of the dune language:
2024-10-11T08:36:28.0127097Z - 1.0 to 1.12
2024-10-11T08:36:28.0128055Z - 2.0 to 2.9
2024-10-11T08:36:28.0128965Z - 3.0 to 3.5
2024-10-11T08:36:28.0368153Z make[1]: *** [Makefile:23: fstar] Error 1
2024-10-11T08:36:28.0372601Z make[1]: Leaving directory '/cygdrive/c/gha/ep2/_work/everparse/everparse/FStar'
2024-10-11T08:36:28.0479079Z make: *** [Makefile:77: everparse] Error 2
2024-10-11T08:36:28.0614278Z *** Error:

This works locally. Seems related to FStarLang/FStar#3503 and FStarLang/FStar#3457

[mtzguido]

That looks like a windows build? The linux build also failed but I can't find the error in the log.