Currently, python-blosc depends on python-cpuinfo which in turn, does not support the mentioned arcs and as a result blosc cannot be built in rawhide after these archs were enabled. Failed build: https://koji.fedoraproject.org/koji/taskinfo?taskID=17002571 These archs should be excluded.
The unnecessary build-time check can be removed - http://pkgs.fedoraproject.org/cgit/rpms/python-blosc.git/commit/?id=3602f24e26109015780e0c7705a197ace9a8981e