namespace::clean fails its tests if Sub::Name or Sub::Util is installed,
see https://rt.cpan.org/Ticket/Display.html?id=107343.
- perl: 5.8.3_nt
- perl: 5.8.3_nt_mb
+ # namespace::clean breaks on threaded 5.8.8
+ # https://rt.cpan.org/Ticket/Display.html?id=107343
+ - perl: 5.8.8_thr_mb
+
# sourcing the files is *EXTREMELY* important - otherwise
# no envvars will survive