In the case of the source-file we have code that handle
the file inline. When we extract the source we do set
the url with that inline data. In get_download_location
that is also used by the bundling code we do then
check against this url and fail.
This adds a step to the build process to bundle
the module sources, used for building the flatpak,
as a runtime extension.
The sources can then be installed like the
debug or translation runtime.
This also adds an option to flatpak-builder
for specifying sources directories. One can specify
source dirctories with the use-sources argument. This
will skip the download part of the processing
and will extract the sources from the given sources
directory directly for further processing.
Those source directories do need the same
structure as the ones that flatpak-builder
creates during processing in .flatpak-builder
and which is also used in the exported sources
runtime.
