pgsql: Create contrib/bool_plperl to provide a bool transform for PL/Pe

Create contrib/bool_plperl to provide a bool transform for PL/Perl[U].

plperl's default handling of bool arguments or results is not terribly
satisfactory, since Perl doesn't consider the string 'f' to be false.
Ideally we'd just fix that, but the backwards-compatibility hazard
would be substantial. Instead, build a TRANSFORM module that can
be optionally applied to provide saner semantics.

Perhaps usefully, this is also about the minimum possible skeletal
example of a plperl transform module; so it might be a better starting
point for user-written transform modules than hstore_plperl or
jsonb_plperl.

Ivan Panchenko

Discussion: https://postgr.es/m/1583013317.881182688@f390.i.mail.ru

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/36058a3c55d2c42a513a53da8140b07cf0893afb

Modified Files
--------------
contrib/Makefile | 4 +-
contrib/bool_plperl/.gitignore | 4 ++
contrib/bool_plperl/Makefile | 39 +++++++++++
contrib/bool_plperl/bool_plperl--1.0.sql | 19 ++++++
contrib/bool_plperl/bool_plperl.c | 30 +++++++++
contrib/bool_plperl/bool_plperl.control | 7 ++
contrib/bool_plperl/bool_plperlu--1.0.sql | 19 ++++++
contrib/bool_plperl/bool_plperlu.control | 6 ++
contrib/bool_plperl/expected/bool_plperl.out | 97 +++++++++++++++++++++++++++
contrib/bool_plperl/expected/bool_plperlu.out | 97 +++++++++++++++++++++++++++
contrib/bool_plperl/sql/bool_plperl.sql | 66 ++++++++++++++++++
contrib/bool_plperl/sql/bool_plperlu.sql | 66 ++++++++++++++++++
doc/src/sgml/plperl.sgml | 47 ++++++++++++-
src/tools/msvc/Mkvcbuild.pm | 5 ++
14 files changed, 502 insertions(+), 4 deletions(-)