It's quite easy to change %Config values - and the same method works on all systems. Just create a file named (say) New_Config.pm:

You should be aware that changing paths in Config.pm has no effect on @INC. The point of the hack in ExtUtils::FakeConfig is to fool other programs about how this Perl has been built. Other programs use Config and act accordingly. For Perl itself it is just a report written at build time, the Perl executable does not read it (unless you start with perl -d as the debugger does use it).