cmake HAVE_GPIO_CDEV_V1 examples

brainflow-dev/brainflow third_party/periphery/CMakeLists.txt :14 

check_symbol_exists(GPIO_GET_LINEEVENT_IOCTL linux/gpio.h HAVE_GPIO_CDEV_V1)

brainflow-dev/brainflow third_party/periphery/CMakeLists.txt :17 

elseif(HAVE_GPIO_CDEV_V1)