Bug#1031771: linphone-desktop: Update check recommends AppImage

[Dennis Filder]

Control: reassign -1 linphone 5.1.65-3
X-Debbugs-CC: Bastian Germann <bage at debian.org>

On Wed, Feb 22, 2023 at 02:15:09PM +0100, Bastian Germann wrote:
> The update check in the "burger menu" should be disabled because it
> downloads the AppImage version of linphone-desktop.

Patching an envvar-overridable early return and warning message into
linphone/coreapi/update_check.c:linphone_core_check_for_update() seems
to me like the easiest way to address this.  It would also function as
a stop-gap for any new mechanisms that try to trigger an update check.

I'll try to have a branch prepared in salsa by Sunday.

Regards.