Previously, SDL would `find_package(libusb)` which would actually overwrite the user preference in the case where both USE_SYSTEM_LIBUSB and USE_SYSTEM_SDL were OFF. This coincidentally also allows SDL to use libusb on Windows.
Previously, SDL would `find_package(libusb)` which would actually overwrite the user preference in the case where both USE_SYSTEM_LIBUSB and USE_SYSTEM_SDL were OFF. This coincidentally also allows SDL to use libusb on Windows.