This patch is a preliminary refactoring for an upcoming patch aimed at
adding new options to this tool, and using long options for these is
more user-friendly. The existing short options gain long flavors, as
of:
* -d/--debug
* -n/--dry-run
* -x/--strip-extension
Author: Atsushi Torikoshi
Reviewed-by: Fujii Masao, Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/d660ef741ce3d82f3b4283f1cafd576c@oss.nttdata.com