Please refer to https://lists.ipfire.org/pipermail/development/2021-December/011796.html and the mails in the same thread before for further details. make.sh needs to be fixed in order to ignore file names when checking for architecture names.
Arne silently fixed this one in https://git.ipfire.org/?p=people/pmueller/ipfire-2.x.git;a=commit;h=59e683df2524917dc443121fb2427ea779bc2062. Thank you, Arne! :-)