I agree with you once that the ANSI spirit is to have a code that can run under
any flavor of OS without beeing modified. That is a minimum set of functions and features that should be avaiable to any distribution.
As far as I know there is no oficial set of modules, for instance, that must come with any perl distribution
or with any basic OS distribution like Unix UX, AIX, Mac, Linux and even(il) windows.
A standard set of modules (and maybe documentation) would help developers to produce final
sw that would run withoung beeing necessary to download and install any specific module (that is default (ANSI) to any distribution.
When talking about Perl I mean that the set of modules that goes with every distribution
and that is tested in every plataform is more important than any syntax issue
because ther Perl language is already very portable (see perldoc perlport)