[APP BUG] "No available displays" error when running headless x11 on linux

Please confirm the following points:

• This report is NOT about the Android apps in the Play Store
• I have searched the project page to check if the issue was already reported

Affected Application

projectM Standalone SDL2 Frontend (includes the Steam app)

Affected Version

No response

Operating System

Linux (Desktop)

Additional Application Details

Application version: 2.0.0
Built/running with projectM4 version: 4.1.0 / 4.1.0
Built against SDL version: 2.26.5 (running with 2.26.5)

Type of Defect

Graphical issue (rendering glitches, black screen, heavy flickering)

Log Output

Initializing subsystem: SDL2 Rendering Window
Could not create SDL rendering window. Error: No available displays
Exception: Could not create SDL rendering window. Error: No available displays

Describe the Issue

Debian12, running headless X11, SDL gives an error that there are "No available displays"

An effective workaround is to set the enviornment variable SDL_VIDEO_X11_XRANDR=0

Fixed in SDL 3.1.10+
https://github.com/libsdl-org/SDL/commit/71099149b8fc062ea0ece232ccdd9f0ee9b3588b

Start by locating the SDL2 rendering-window initialization and the project's SDL dependency configuration. Reproduce the failure on headless Debian 12 with X11, then compare behavior with SDL_VIDEO_X11_XRANDR=0 and the referenced upstream SDL fix. Done means the standalone frontend handles this environment without the reported error, or the supported workaround is clearly documented.