Add check for switcheroo functionality when multiple GPUs are detected

Some Linux distributions do not enable switcheroo-control by default, despite it being part of most system installations these days.
This implements a simple check to warn the user of degraded functionality if switcherooctl exists but returns no GPU list (as is the case when the service doesn't run).

For more information, see https://man.archlinux.org/man/switcherooctl.1.en

indra/newview/linux_tools/wrapper.sh

@@ -107,6 +107,11 @@ else
     echo "Please install wine to enable full voice functionality."
 fi
 
+# Check if switcheroo is needed
+if [[ -d /sys/class/drm/card1 ]] && command -v switcherooctl >/dev/null 2>&1 && [[ "$(switcherooctl)" == "" ]]; then
+  notify-send "Automatic GPU selection is not available" "Please enable switcheroo-control.service"
+fi
+
 # Run the program.
 # Don't quote $LL_WRAPPER because, if empty, it should simply vanish from the
 # command line. But DO quote "${ARGS[@]}": preserve separate args as