Not really unfortunately because your script does a lot of things and patch stuff, so I don't really know where the problem can come from. It says that this particular fork-slug package is missing, so you'd need to check why it's not being included.

Actually you have a line that lists packages there and fork-uslug is not being included, so maybe that's where? arch-pkgbuilds/PKGBUILD at 60c7def2cb97251bd06a521a010c0aec8dc7fd3c · alfredopalhares/arch-pkgbuilds · GitHub