Add global option --time to track execution

This prints a simple line after a command ends, providing
information about how long it executed for using real wall
clock time. Its mostly useful for looking at sync times.

Change-Id: Ie0997df0a0f90150270835d94b58a01a10bc3956
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed