version number part (i.e., "<directory>/perl"). Use this to
substitute #! lines in your perl5 scripts.
Requested and reviewed by: ache
(2) Add new variable WRKDIRPREFIX (defaults to ""). The "work"
directories are now in ${WRKDIRPREFIX}${.CURDIR}/work by default.
You can have a read-only ports tree (modulo any broken ports that
write something to places other than ${WRKDIR}) by setting this to
a writable location.
Ports that set WRKDIR explicitly should append this to front so
they will work when the user has WRKDIRPREFIX set.
Reviewed by: Toshihiko Kodama <kodama@ayame.mfd.cs.fujitsu.co.jp>