Dropping X11 VCL backend

[Ilmari Lauhakangas]

On 29.12.2020 11.11, julien2412 wrote:
> I use gen rendering when trying to be nearer of a Windows config.
> Indeed, I'm on pc Debian x86-64 with master sources and by default it uses
> gtk3.
> Badfully, gtk3 uses accessibility part which has been quite broken since
> years (but I suppose no one will want to remove it). So sometimes, I got
> some assertion or bug with gtk3 which prevents me to reproduce the real bug.
> There's also kf5 rendering (corresponding to kde, I don't know why it's not
> called "kde5") which doesn't use accessibility but need a lot of extra libs
> to install (there are also all related Plasma and Wayland things that I
> don't know enough so sometimes it's not easy to reproduce kde specific
> bugs).

kf5 comes from KDE Frameworks 5.

The extra libs to install are (on Debian & Ubuntu):

qtbase5-dev libkf5coreaddons-dev libkf5i18n-dev libkf5config-dev 
libkf5windowsystem-dev libkf5kio-dev

> Finally gen rendering which "seem" (perhaps I'm wrong here) not to use extra
> libs and in which some window dialogs are not modal (I don't know why) is a
> good complement to test (even if I dislike UI above all open file window
> dialog).

Yeah, but if gen/x11 stops having a practical use, then it will merely 
be an extra thing to test with its own quirks, causing constant 
maintenance effort.

Ilmari