No, there's no change at all in the portability.
This looks like a fallout from switching from Make to Hadrian.
ghcii.sh was created as an artifact of make install. Hadrian seems to lack this step.
Note that this script is nothing magical, it's just a hack around how signal handlers in Native windows and Cygwin processes are handled.
I'm not entirely sure it's still needed with the new I/O manager, however that's not on yet by default..
Anyways support should probably be added to Hadrian.
Kind regards,
Tamar