Not guaranteed to build against libraries built with bundled Tcl/Tk source

[crcox]

On one of my Ubuntu 14.04 boxes, there is a system-level install of Tcl/Tk 8.6.1. Lens is building against this rather than the distributed 8.6.4.

I've ensured that all #include "tcl.h" and #include "tk.h" statements in the Lens source use "" and not <>, and checked that gcc is getting the local lib directory:

gcc -o /home/chris/src/lens/Bin//lens-2.63 \
    ../Obj//main.o ../Obj//type.o ../Obj//util.o ../Obj//network.o \
    ../Obj//connect.o ../Obj//example.o ../Obj//act.o ../Obj//train.o \
    ../Obj//object.o ../Obj//command.o ../Obj//control.o ../Obj//display.o \
    ../Obj//graph.o ../Obj//parallel.o ../Obj//networkCom.o \
    ../Obj//connectCom.o ../Obj//exampleCom.o ../Obj//trainCom.o \
    ../Obj//objectCom.o ../Obj//displayCom.o ../Obj//graphCom.o \
    ../Obj//parallelCom.o ../Obj//canvRect.o ../Obj//extension.o \
     -L/home/chris/src/lens/usr/local/lib \ # relevant line
     -ltk8.6 -ltcl8.6 -lm -lX11 -export-dynamic -ldl