Note: one goal is to have to edit fewer version numbers in source
files for each release.
We may be able to generate some files by the build procedure (CMake)
to avoid editing them in the future (1.5.0 or later).
macOS Big Sur 11.3 introduced a new "security feature" such that
app bundles created from existing bundle templates in downloaded
files (tar distibutions, expanded) could no longer be executed
without unsetting the "quarantine" attribute. This commit fixes
this by creating all bundles from scratch.
Known *workaround* for older tarballs and snapshots:
$ xattr -d -r com.apple.quarantine xxx.app
