Disable the ntk driver if tck/tk does not exists, or if user specifyed --disable-tcl or --disable-tk.
Disable the ntk driver if tck/tk does not exists, or if user specifyed --disable-tcl or --disable-tk.

svn path=/trunk/; revision=3331

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot