Can create a cert with no serial number?

[Robert Moskowitz <rgm@xxxxxxxxxxxxxxx>]

I tried putting in my conf:

serial = none

and that made an error.

Best I have done is a serial of length 1 byte.  But in my work, the 
subject or SAN provide uniqueness and CRLs will not be used.  So want to 
see if I can create a cert with NO serial number.

Thanks