How do I solve this WRKDIR problem?

[Paul Schmehl]

I'm trying to update the devel/byaccj port, which I maintain.  The new version 
has made some subtle changes in naming, which have thrown me for a loop;

PORTNAME=  byaccj
PORTVERSION=  1.15
DISTFILES= byaccj1.15_src.tar.gz

WRKDIR is work/byaccj1.15 when the files are extracted.

If I don't define WRKSRC, it's byaccj-1.15.  If I define it as 
${PORTNAME}${PORTVERSION}, it's still byaccj-1.15.  Hardcoding it doesn't seem 
like the right answer, but what is?

-- 
Paul Schmehl, Senior Infosec Analyst
As if it wasn't already obvious, my opinions
are my own and not those of my employer.
*******************************************
"It is as useless to argue with those who have
renounced the use of reason as to administer
medication to the dead." Thomas Jefferson