The --allow-missing-runtimes options will allow flatpak builder to
not abort immediately if the sdk or runtime for the app being built
are missing.
This option will be useless when building anything in the modules
section of the app manifest. The calls to flatpak-build will fail
because of the missing sdk.
However, it may be useful when an application does not require
building anything inside the sandbox, and the application files
will be installed via other means.
This disables build-args support, which is nice when building things
on e.g. a shared build-machine, where we don't want the build to
be able to break out of the sandbox (by specifying e.g. --share=network).
Stop building at a specified module from the json file.
This is useful during development. For instance, you can do --stop-at=main-app
to build all the dependencies into the appdir, then you can do a build of an
already checked out git repo (possibly with changes).
