* First crack at light sensor support for Linux
* Add light-sensor support to most Linux input drivers
* Fix a compiler error
- Whoops, forgot to declare `sdl`
* Refactor linux_illuminance_sensor_t
- Allow the poll rate to be specified
- Poll the sensor on a separate thread
- Open a file handle each time we poll the sensor, since sysfs doesn't update the contents of an existing handle
* Set the `done` flag when closing the light sensor
- Whoops
* Avoid a division by zero when updating the poll rate of an existing sensor
* Don't try to open illuminance sensors from ".", "..", or hidden files
* Never mind
* Fix some silly mistakes
* Skip hidden files, ".", and ".."
* Cancel the sensor poll thread mid-sleep when closing it
- POSIX says it's fine
* Add to CHANGES.md
* Address feedback given on PR
* Use libretro-common's file system instead of stdio
