Conditionally compiles the nn library if Qhull was not found or was disabled with --with-qhull=no (or --without-qhull)
Conditionally compiles the nn library if Qhull was not found or was disabled with --with-qhull=no (or --without-qhull)

svn path=/trunk/; revision=4504

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