if co_stacksize was > 32767 (the maximum value
which can be stored in 16 bits (signed)),
the PyCodeObject would be written wrong.
So on the second import (reading the .pyc)
would cause a crash.

Since we can't change the PYC magic, we
go on (silently), but don't write the file.
This means everything will work, but
a .pyc will not be written and the file will need
to be parsed on each import.

I will backport.