Made the free/used memory polling time configurable through the
"delay" option.
pkgsrc changes:
modified the rc.d script to work on systems without the NetBSD's rc.d
system.
"Swapd" is a daemon that watches free memory and manages swap files. If free
memory drops too low, additional swap files are created. Additionally, if there
is too much free memory, swap files are deactivated and disk space may be
reclaimed.