NO_OVERLAY define becomes EMU_OVERLAY which enables the overlay instead of disabling it. disable_overlay.txt moved to steam_settings.
Found on sanctum2, returning 0 in XPending & XEventsQueued make the SDL do something else than polling events and makes lag the event loop. Now the event loop returns 0 when there are no more events.
Use LD_PRELOAD=$PWD/libsteam_api.so app_name to load overlay.