warnings as XS

[rurban]

Rewrite warnings.pm which is generated as pure XS. esp. to save memory

A regular XS extension, with a stable set of .xs and .h files, and a warnings_xs.PL regen and definition script (prev. regen/warnings.pl), which updates the keys in place. required gperf so far, as with Config as XS.

Seperate into a pure read-only perfect hash, and a user-extendable warnings::register hash. Check against Carp in XS and PP Carp.

See branches feature/CM-367-cperl-warnings-xs-carp and feature/CM-370-cperl-warnings-xs

[rurban]

Status: One small nasty bug left, in 9enabled