The point will be for a packager to create a unique build ID to identify
the build or provenance. I also add a revision number so that we can
identify 2 builds from the same version/commit, same maker and platform.
It will also be used later to check for new versions (see "phone home"
feature #2584).
Separating autotools and meson commits for easy backport.
(cherry picked from commit 73c09ebb32)
Since commit 9fdf35550b, I removed the GIMP_APP_GLUE_COMPILATION check
because we need to have the whole versioning info from the new debug
widget. It just makes sense to go further and just make this a proper
internal API to get version information.
