* Update sdl2-compat to 2.32.64 (steamrt/tasks#905)
* "Classic" SDL2 is still the default in this branch, but sdl2-compat is likely to become the default in a future release (steamrt/tasks#774)
### Container runtime
* "Capture" GBM backend modules from the graphics provider. These are needed for accelerated EGL in some Nvidia driver versions, and for some streaming-related use-cases since Mesa 24.3.0. (steamrt/tasks#900, [steam-runtime#797](https://github.com/ValveSoftware/steam-runtime/issues/797))
* Optionally "capture" OpenXR layers from the graphics stack provider into the container, similar to Vulkan layers. Like its equivalent for OpenXR runtimes, this is considered experimental, and could cause regressions by pulling in layers with non-trivial shared library dependencies, so for now it is only done if requested by setting environment variable `PRESSURE_VESSEL_IMPORT_OPENXR_1_LAYERS` to `1`. (steamrt/tasks#734, [steam-runtime#765](https://github.com/ValveSoftware/steam-runtime/issues/765))
* Always use the Steam Runtime's time zone info `/usr/share/zoneinfo`, even if the host OS's glibc defaults to something non-FHS ([steam-runtime#795](https://github.com/ValveSoftware/steam-runtime/issues/795))
* pressure-vessel includes local copies of `srt-logger`, `s-r-check-requirements`, `s-r-steam-remote` (steamrt/tasks#669)