include: add uinput.h header as well

Older kernels don't have UI_GET_SYSNAME, and upstream is adding a few more
ioctls to the uinput code. So ship the header we're using to avoid compilation
errors.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
tools: add an event counter program

A tool to count events and print basic statistics. Example output:

Input device ID: bus 0x3 vendor 0x56a product 0x27
Input device name: "Wacom Intuos5 touch M Pen"
Events received:   630
Axis/key statistics:
	EV_ABS:
		ABS_X               384 (62.2% of type, 61.0% of total)
		ABS_Y               482 (78.1% of type, 76.5% of total)
		ABS_PRESSURE        228 (37.0% of type, 36.2% of total)
		ABS_DISTANCE        164 (26.6% of type, 26.0% of total)
		ABS_TILT_X          160 (25.9% of type, 25.4% of total)
		ABS_TILT_Y           80 (13.0% of type, 12.7% of total)
		ABS_MISC              1 (0.2% of type, 0.2% of total)
	EV_KEY:
		BTN_TOOL_PEN          1 (3.7% of type, 0.2% of total)
		BTN_TOUCH            26 (96.3% of type, 4.1% of total)
Per event type statistics:
	Events with/without EV_ABS data: 13/617 (2.1%/97.9%)
	 1 EV_ABS events per SYN_REPORT:  114 (18.5% of type, 18.1% of total)
	 2 EV_ABS events per SYN_REPORT:  220 (35.7% of type, 34.9% of total)
	 3 EV_ABS events per SYN_REPORT:  198 (32.1% of type, 31.4% of total)
	 4 EV_ABS events per SYN_REPORT:   77 (12.5% of type, 12.2% of total)
	 5 EV_ABS events per SYN_REPORT:    7 (1.1% of type, 1.1% of total)
	 7 EV_ABS events per SYN_REPORT:    1 (0.2% of type, 0.2% of total)
	Events with/without EV_KEY data: 603/27 (95.7%/4.3%)
	 1 EV_KEY events per SYN_REPORT:   27 (100.0% of type, 4.3% of total)

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>