1.90.8 and backend shenanigans

[JamesWrigley]

I began the bindings update to 1.90.8 and ran into a bunch of things that needed fixing in our backends, so I decided to try using the official GLFW/OpenGL3 backends instead. And amazingly, they seem to work :octopus: This isn't ready to merge yet but I'm opening it for transparency. demo/demo.jl should work, but not example/demo.jl yet.

How to test it:

• Clone my cimguipack-update branch of Yggdrasil (https://github.com/JuliaPackaging/Yggdrasil/pull/8870)

• Build CImGuiPack locally with: julia +1.7 build_tarballs.jl <platform> --deploy=local. Change the platform to your desired one, for example (in a project with BinaryBuilder and BinaryBuilderBase installed):

  julia +1.7 --project=@bb build_tarballs.jl x86_64-linux-gnu --deploy=local # Linux
  julia +1.7 --project=@bb build_tarballs.jl x86_64-apple-darwin --deploy=local # OSX
  julia +1.7 --project=@bb build_tarballs.jl x86_64-w64-mingw32 --deploy=local # Windows

  If you get configure errors about cxx_std_20, pick a target that's in this CI list that matches your system: https://buildkite.com/julialang/yggdrasil/builds/11093. For example, on my system I had to use x86_64-linux-gnu-cxx11-julia_version+1.11.0.

• Clone this branch, ] dev ./LibCImGui.jl and ] dev CImGuiPack, and run demo/demo.jl. Docking and multiple viewports should work.

[JamesWrigley]

Fixes #123. Sneaky proof using the new test engine wrapper :smirk:

[JamesWrigley]

While fixing the existing tests and getting CI to pass I realized that package extensions were only added in 1.9... I don't think I can be bothered supporting Requires and all that for older versions so I just bumped the minimum Julia version. There's still two failures on nightly for OSX and Ubuntu, but they both seem to be issues with loading GLFW.

[JamesWrigley]

I tried to add x86 tests to CI, but got this error when creating a GLFW window: Invalid window size -389703880x100 Not sure what's going on there, AFAICT it's unrelated to CImGui. But we weren't testing x86 before anyway so I don't think it's a blocker.