* tools/gpgconf.c: Include exechelp.h.  New option --show-versions.
(get_revision_from_blurb): New.
(show_version_gnupg): New.
(show_version_libgcrypt): New.
(show_version_gpgrt): New.
(show_versions_via_dirmngr): New.
(show_versions): New.
* dirmngr/dirmngr.c (main): New internal option --gpgconf-versions.
(get_revision_from_blurb): New.
(gpgconf_versions): New.