change in system call in 1.8.1?

[Jack Howarth]

   I noticed tonight that my proposed packaging for
pymol was broken under MacPorts 1.8.1. 

http://trac.macports.org/ticket/21376

In particular, the instances of...

system "cd setup; cp Rules.osx-fink ../Rules.delsci"
system "make -f Makefile.delsci"

can no longer find the files Rules.osx-fink and Makefile.delsci.
I now have to reformulate this as...

system "cd  ${worksrcpath}/setup; cp Rules.osx-fink ../Rules.delsci"
system "cd  ${worksrcpath}; make -f Makefile.delsci"

Is this expected behavior in MacPorts 1.8.1?
            Jack