• Chg : A large chunk of boilerplate XS code, which is also used in
  other XS modules, has been factored out of the main .xs file
  to a collection of .h files in the xsh subdirectory.
  
• Fix : [RT #128989] : Bleadperl v5.25.3-266-g1d7e644 breaks V::M.
  Len magic is no longer called for negative array indices
  fetches, so the relevant tests are now skipped.
  Thanks Andreas Koenig for reporting.