Tiny mouse cursor in the app window with 125% fractional scaling enabled in Wayland

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

The mouse cursor is tiny with 125% fractional scaling enabled in Wayland session, as shown in the screen recording below:

https://github.com/libretro/RetroArch/assets/1403194/5a6b35d8-f6cf-4abc-91e7-2cccc435c6d9

I tried setting XCURSOR_THEME=Adwaita and XCURSOR_SIZE=32 environment variables to match my system setting, but it doesn't work.

*This issue is not occurring if I force the app to run in XWayland mode.

**This issue is not occurring under Wayland in fullscreen mode, as shown in the screenshot below, but the cursor theme is not matching with the system:

Expected behavior

The mouse cursor scale correctly in Wayland with fractional scaled display.

Actual behavior

The mouse cursor doesn't scale correctly under Wayland with fractional scaled display, and also doesn't respect XCURSOR_SIZE environment variable.

Steps to reproduce the bug

1. Using Wayland.
2. Enable fractional scaling.
3. Open the app in native Wayland mode. See the tiny cursor inside the app window.

Bisect Results

I just start using RetroArch today on PC (usually on my Android box). I am not sure when this happened.

But running the app in verbose mode gives me 2 Wayland related info:

[INFO] [Wayland]: Compositor doesn't support zxdg_decoration_manager_v1 protocol
[INFO] [Wayland]: fractional_scale_v1 enabled

Version/Commit

• RetroArch: 1.19.0/00b8a5f

I install the app from Flathub.

Environment information

• OS: openSUSE Tumbleweed, Linux 6.9.3-1-default

Start by reproducing the tiny cursor in a native Wayland window with 125% fractional scaling, using the verbose output and environment settings described in the issue. Trace the Wayland cursor and fractional-scale handling; done means the cursor scales correctly and respects the configured cursor size without regressing fullscreen or XWayland behavior.