PORTREVISION or PORTEPOCH are defined.
Most of these Makefiles were defining DISTNAME and WRKSRC (and
sometimes EXTRACT_SUFX) -- change those to define DISTFILES only.
Also, some of the WRKSRC lines were not even necessary, as they were
defining it to the default value.
Instigated by: Peter Pentchev <roam@orbitel.bg> and kris
