Bug#990618: Patch for GNOME Maps failing to start in Bullseye

[Simon McVittie]

On Mon, 30 Aug 2021 at 14:26:17 +0000, John Scott wrote:
> I've attached a patch that's ready to address this issue in Bullseye.

Thanks for tracking down the right commit.

There have been several new upstream releases from the 3.38.x stable
branch, including this change, so I'm inclined to see whether the
release team would accept an update to 3.38.6 instead of cherry-picking
this single change - the other changes in 3.38.6 seem to be correctly
bugfix-only, even if some of them are for things we would not normally
backport. This specific change seems to be the entirety of the 3.38.4 ->
3.38.5 update.

> Description: mapView: Don't try to set aerial tiles if not available
>  Safe-guard against setting the aerial tile source

For future reference, the GNOME team mostly uses the dialect of DEP-3 that
resembles `git format-patch` output, for better interop with `gbp pq`.

One day I should probably propose an update to DEP-3 recommending that
format as the default in general, because it's no more difficult to
hand-write than the Debian-specific dialect, and interoperates better
with typical git tools (and upstreams).

Thanks,
    smcv