EMACS_USECS (TIME) is an rvalue for the microseconds component of TIME.
This returns zero if EMACS_TIME doesn't have a microseconds component.
EMACS_SET_USECS (TIME, MICROSECONDS) sets that to MICROSECONDS.
EMACS_USECS (TIME) is an rvalue for the microseconds component of TIME.
This returns zero if EMACS_TIME doesn't have a microseconds component.
EMACS_SET_USECS (TIME, MICROSECONDS) sets that to MICROSECONDS.