fix FTBS on duplicate ARRAY_SIZE
Some platforms (eg. SunOS) already define this macro, so we'll have to check whether it's already defined.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
Some platforms (eg. SunOS) already define this macro, so we'll have to check whether it's already defined.