* Make use of `PackageUpdater` more efficient by avoiding multiple calls of
`addDepsAndProvidesFromOtherPackage`
* Fix leaving old provides in the database by splitting the update via new
`beginUpdate()` and `endUpdate()` functions
This might be useful to avoid blocking threads in the thread pool just for
waiting on a global lock. It might also be useful to allow stopping build
actions while they're waiting for a lock.
When adding a new database when reloading the config at runtime the
architecture must be passed when creating the database. Otherwise we end up
with the new database sharing the internal storage with the x86_64 database
which leads to very confusing behavior.
* Do HTTP head request first when loading database from mirror to avoid
downloading the full database all the time
* Use the last modification date of the local database file because with
the persistent storage even local database reloads became a bit expensive
Simply adding `--sign` to the `makepkg` flags doesn't work because it would
require setting up GPG within the chroot environment (of `makechrootpkg`).
When debugging it is anyways annoying that `makepkg` sends the `gpg` output
to `/dev/null`. This way the logs are preserved.
* Can not use a normal mutex because we don't want to tie the resources to
a specific thread (and instead e.g. to a build action which might not be
executed by a single thread)
* A semaphore would do that but libstdc++ only supports it as of GCC 11 and
besides it wouldn't distinguish between shared and exclusive locking
Martchus