min version of gtk3

[Jan-Marek Glogowski]

Am 01.12.2017 um 13:43 schrieb Caolán McNamara:
> There was a theming change in gtk3 3.20.0 and we support the old scheme
> before that point and the new scheme after that point. 
> 
> Things would be a lot simpler if the min version of gtk3 was 3.20.0, is
> there any distributions or individual devs for whom that would cause a
> problem ?

Ubuntu Xenial (16.04) has 3.18.9-1ubuntu3, which I backported for our
trusty master tinderbox.

I guess we won't deliver any 6+ version of LO for trusty and won't have
problems with our next OS release.

You want to drop Gtk+ < 3.20.0 support in or after 6.0?

Jan-Marek