[time-nuts] Generate 1 PPS signal on serial port

[Eugen]

Probably this was asked before but in searches I only find how to use
an external 1 PPS GPS signal for NTP synchronization.

Having a Linux/FreeBSD PC synchronized using NTP/chrony, what would be
the best way of generating an output 1 PPS signal on a (hardware)
serial port ?

For timing I've seen the standard libc functions from <sys/time.h>, like
setitimer(), but maybe there are better ways for generating precise
delays.