Oh, well, that sucks. Have to go to the source code and even then only in the very latest development version. At least I know now, thanks for the link.

Well, you can always turn on taint, which will remove . from @INC, but most code isn't prepared to deal with taint so ...

Well, you don't have to go to the source in the latest version, its a configuration option, you just gotta configure the configuration

For arbitrary older versions, all you do is "backport" from the current version, which all it really is applying a patch, which you produce from the current dev version ... but thats only if you want to have a configuration option like the latest version

Removing "." from @INC can be as simple grepping the source (perl.c) and commenting out   S_incpush(aTHX_ STR_WITH_LEN("."), 0);