NixOS keeps the GPU driver's EGL vendor files and external-platform files
under /run/opengl-driver, which glvnd and NVIDIA's driver inside the FHS
environment do not search. glvnd then only knows Mesa, and NVIDIA cannot open
X11 displays because its X11 support is the egl-x11 external platform. The
client fell back to Mesa's software rasterizer: garbled text in the client and
no way to present the game's NVIDIA Vulkan frames.
When /run/opengl-driver provides them, prepend those directories to
__EGL_VENDOR_LIBRARY_DIRS and __EGL_EXTERNAL_PLATFORM_CONFIG_DIRS, keeping the
FHS paths and any caller-provided value after them.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
