xinput.c:277:6: warning: no previous prototype for ‘is_pointer’ [-Wmissing-prototypes]
  277 | Bool is_pointer(int use)
      |      ^~~~~~~~~~
xinput.c:282:6: warning: no previous prototype for ‘is_keyboard’ [-Wmissing-prototypes]
  282 | Bool is_keyboard(int use)
      |      ^~~~~~~~~~~
xinput.c:287:6: warning: no previous prototype for ‘device_matches’ [-Wmissing-prototypes]
  287 | Bool device_matches(XIDeviceInfo *info, char *name)
      |      ^~~~~~~~~~~~~~
test_xi2.c:254:1: warning: no previous prototype for ‘test_sync_grab’ [-Wmissing-prototypes]
  254 | test_sync_grab(Display *display, Window win)

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>