pgsql: Teach regular expression operators to honor collations.

Teach regular expression operators to honor collations.

This involves getting the character classification and case-folding
functions in the regex library to use the collations infrastructure.
Most of this work had been done already in connection with the upper/lower
and LIKE logic, so it was a simple matter of transposition.

While at it, split out these functions into a separate source file
regc_pg_locale.c, so that they can be correctly labeled with the Postgres
project's license rather than the Scriptics license.  These functions are
100% Postgres-written code whereas what remains in regc_locale.c is still
mostly not ours, so lumping them both under the same copyright notice was
getting more and more misleading.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/1e16a8107db9a50435b39e09c6f9c52c45e63e1a

Modified Files
--------------
doc/src/sgml/charset.sgml                        |   33 +-
src/backend/libpq/hba.c                          |    3 +-
src/backend/regex/Makefile                       |    3 +-
src/backend/regex/regc_locale.c                  |  165 ------
src/backend/regex/regc_pg_locale.c               |  649 ++++++++++++++++++++++
src/backend/regex/regcomp.c                      |   12 +-
src/backend/regex/regexec.c                      |    3 +
src/backend/tsearch/spell.c                      |    5 +-
src/backend/utils/adt/regexp.c                   |   42 ++-
src/include/regex/regex.h                        |    4 +-
src/test/regress/expected/collate.linux.utf8.out |   74 +++
src/test/regress/sql/collate.linux.utf8.sql      |   18 +
12 files changed, 819 insertions(+), 192 deletions(-)