Tk directory-finding patch by Benjamin Drung.
Fixes the following: Guess the correct directory in Debian/Ubuntu fails. Replacing all tcl by tk does not lead to a correct directory: /usr/share/tcltk/tcl8.5 -> /usr/share/tktk/tk8.5 The correct directory is /usr/share/tcltk/tk8.5
Authored by: efiring 2009-10-05
Parent: [r7845]
Child: [r7847]
