redshift-gtk: use Ayatana AppIndicator3 instead of App Indicator3

[kenhys]

libappindicator was deprecated and it will be removed in the
future Debian release.

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=895037

There is a successor API compatible library - Ayatana Indicator.

https://ayatanaindicators.github.io/code/

[CameronNemo]

Thanks for the patch. Does this affect any existing distros which might ship the older library but not the newer one? If so, is there a way to keep compatibility with both?

[kenhys]

Here are current status of Ayatana Appindicator:

Debian 9(old-stable): not available
Debian 10(stable): available
Ubuntu 16.04(xenial): not available
Ubuntu 18.04(bionic): available
Ubuntu 19.10(eoan): available
Ubuntu 20.04(focal): available

It is ok to migrate Ayatana because it is available on stable release.

If you want to keep compatibility with both, it may better to try (Ayatana Appindicator) and fallback to AppIndicator .

[jonls]

Yeah it seems like it should be easy to try Ayatana first then fallback to the old import since the APIs are supposedly compatible?

[jonls]

• Fallback to old module.
• Some of the documentation mentions appindicator which should be updated I think.
• Needs a rebase on master to fix CI issues.

[hartwork]

@kenhys applied in Gentoo at gentoo/gentoo@08e2652 , thanks for the patch!