Function::Fallback::CoreOrPP provides functions that use non-core XS modules
(for best speed, reliability, feature, etc) but falls back to those that use
core XS or pure-Perl modules when the non-core XS module is not available.

This module helps when you want to bootstrap your Perl application with a
portable, dependency-free Perl script. In a vanilla Perl installation (having
only core modules), you can use App::FatPacker to include non-core pure-Perl
dependencies to your script.