utils: Create _srt_filter_gameoverlayrenderer_from_envp()
With this new function we can avoid repeating the same code over and over.
While working on https://gitlab.steamos.cloud/steamrt/steam-runtime-tools/-/commits/wip/detect_platform_and_lib I tried to create a more common _srt_run_sync()
but, due to the small differences between all the current implementations, I reverted the changes and decided to fallback to just _srt_filter_gameoverlayrenderer_from_envp()
.
Maybe having a _srt_run_sync()
/_srt_run_helper()
will be an improvement for the future.