I asked for the makefile to a few of the testers, but couldn't get it. But now that you say it... checked the makefile generated on my system and found out the problem. What the heck. All because of the code generating META.yaml, with my name:
494: $(NOECHO) $(ECHO) 'license: ~' >> META_new.yml
495: $(NOECHO) $(ECHO) 'author: ' >> META_new.yml
496: $(NOECHO) $(ECHO) ' - Alberto Simões <email@example.com>' >
497: $(NOECHO) $(ECHO) 'generated_by: ExtUtils::MakeMake
+r version 6.44' >> META_new.yml
498: $(NOECHO) $(ECHO) 'distribution_type: module' >> META_ne
And, yes, this fails for just a few systems (mainly VMS and Solaris). Solved, in any case. I need to change my name.