pgsql: Integrate pg_bsd_indent into our build/test infrastructure.

Integrate pg_bsd_indent into our build/test infrastructure.

Update the Makefile and build directions for in-tree build,
and add Meson build infrastructure.  Also convert the ad-hoc
test target into a TAP test.

Currently, the Make build system will not build pg_bsd_indent
by default, while the Meson system will.  Both will test it
during "make check-world" or "ninja test".  Neither will install
it automatically.  (We might change some of these decisions later.)

Also fix a few portability nits noted during early testing.

Also, exclude pg_bsd_indent from pgindent's purview; at least for
now, we'll leave it formatted similarly to the FreeBSD original.

Tom Lane and Andres Freund

Discussion: https://postgr.es/m/3935719.1675967430@sss.pgh.pa.us
Discussion: https://postgr.es/m/20200812223409.6di3y2qsnvynao7a@alap3.anarazel.de

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/156c049beed9d3f243cdceaf89456ea6a2995493

Modified Files
--------------
GNUmakefile.in                                 |  2 +-
src/Makefile                                   |  2 +
src/meson.build                                |  2 +
src/tools/pg_bsd_indent/.gitignore             | 12 ++---
src/tools/pg_bsd_indent/Makefile               | 62 +++++++++++++++++---------
src/tools/pg_bsd_indent/README                 | 37 +++++++++++++++
src/tools/pg_bsd_indent/README.pg_bsd_indent   | 30 -------------
src/tools/pg_bsd_indent/args.c                 |  2 +-
src/tools/pg_bsd_indent/indent.c               |  6 +--
src/tools/pg_bsd_indent/indent.h               |  2 +-
src/tools/pg_bsd_indent/meson.build            | 40 +++++++++++++++++
src/tools/pg_bsd_indent/t/001_pg_bsd_indent.pl | 53 ++++++++++++++++++++++
src/tools/pgindent/exclude_file_patterns       |  4 ++
13 files changed, 188 insertions(+), 66 deletions(-)