Alot can be accomplished by testing the system configuration while the Makefile.PL is running. You can check their versions there. Also, the 'use Config' module tells you quite a a bit about the installtion. The fields PERL_REVISION, PERL_VERSION, PERL_SUBVERSION will give you a precise version of perl. $ENV{LANG} might give you a hint as to whether it's a non-English locale.