create new unicode props as defined in POSIX spec (optionally use them in the regex...

create new unicode props as defined in POSIX spec (optionally use them in the regex engine)

Perlbug #60156 and #49302 (and probably others) resolve down to the problem
that the definition of \s and \w and \d and the POSIX charclasses are different
for unicode strings and for non-unicode strings. This broke the character class
logic in the regex engine. The easiest fix to make the character class logic sane
again is to define new properties which do match.

This change creates new property classes that can be used instead of the
traditional ones (it does not change the previously defined ones). If the
define in regcomp.h:

#define PERL_LEGACY_UNICODE_CHARCLASS_MAPPINGS 1

is changed to 0, then the new mappings will be used. This will fix a bunch
of bugs that are reported as TODO items in the new reg_posixcc.t test file.

p4raw-id: //depot/perl@34769