pgsql: Minor improvements for reformat_dat_file.pl.

Minor improvements for reformat_dat_file.pl.

Use Getopt::Long in preference to hand-rolled option parsing code.

Also, remove "-I .../backend/catalog" switch from the Makefile
invocations.  That's been unnecessary for some time, and leaving it
there gives the false impression it's needed in manual invocations.

John Naylor (extracted from a larger but more controversial patch)

Discussion: https://postgr.es/m/CACPNZCsHdcQN2jQ1=ptbi1Co2Nj3aHgRCUMk62=ThgWNabPY+Q@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/27aaf6eff49a6348408476652911fe4acceffc71

Modified Files
--------------
src/include/catalog/Makefile             |  7 ++----
src/include/catalog/reformat_dat_file.pl | 43 +++++++++++---------------------
2 files changed, 16 insertions(+), 34 deletions(-)