How to extract tcl src

[Stephen Montgomery-Smith]

I am trying to update graphics/togl.  I am running into the following issue.

The togl configure file accesses /usr/local/lib/tcl8.5/tclConfig.sh, and 
figures out that the port was built in 
/usr/ports/lang/tcl85/work/tcl8.5.8.  It wants to access that directory.

How do I tell the Makefile in the port to make sure that I have done 
something like "cd /usr/ports/lang/tcl85 && make extract"?