rsx: Make X11 optional on Linux

[linkmauve]

This makes it possible to build rpcs3 on a pure Wayland system, without the Xlib installed.

[arabek]

[ on branch (master) ]$ gitcopr 7018
remote: Enumerating objects: 25, done.
remote: Counting objects: 100% (25/25), done.
remote: Compressing objects: 100% (19/19), done.
remote: Total 25 (delta 6), reused 23 (delta 6), pack-reused 0
Unpacking objects: 100% (25/25), done.
From https://github.com/RPCS3/rpcs3
 * branch                refs/pull/7018/merge -> FETCH_HEAD
Switched to a new branch '7018'
[ on branch (7018) ]$ make-rpcs3 
(…)
[100%] Linking CXX executable ../bin/rpcs3
[100%] Built target rpcs3

Builds just fine on X11

[amayra]

there any different between pure Wayland and X11 or XWayland build ?

[linkmauve]

So, Wayland is a protocol, X11 is a protocol. Xwayland is a build of the Xorg server allowing you to run any X11 program on a Wayland compositor.

This PR only makes it so a user using only Wayland can build rpcs3 without having to drag all of the X11 dependencies. Both will work on Wayland and X11, but when no X11 headers are found the resulting binary will only work on Wayland.

[escalade]

You need X11 libraries/headers to build Mesa with OpenGL support. What we really need is optional OpenGL support.

#6740

[linkmauve]

No you don’t, since glvnd introduced the new libOpenGL ABI you can build Mesa with desktop OpenGL support without depending on libGLX or X11 libraries.

#6835 would be nice to fix though, I might give it a try after that.

[escalade]

With latest Mesa and libglvnd git:

meson.build:396:4: ERROR: Problem encountered: Cannot build GLX support without X11 platform support and at least one OpenGL API

EDIT: I suppose GLX isn't needed at all anymore. Will try this out.

[kd-11]

The check for either wayland or X11 is still missing too. You should require at least one of them; else no compilation. You need to add it to cmake file since X11 is now not required.

[kd-11]

See this comment.

[linkmauve]

Hi, this should be all done now. :)

Sorry for not reacting earlier, I’ve been pretty busy organising for the general strike in France lately.

[kd-11]

No rush really, its understandable you may have more important things to do. Will review as soon as possible.