watch.c:255:14: warning: no previous declaration for 'get_time_usec' [-Wmissing-declarations]
watch.c:303:6: warning: no previous declaration for 'output_header' [-Wmissing-declarations]
watch.c:364:5: warning: no previous declaration for 'run_command' [-Wmissing-declarations]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>