Fix to ensure that BUILD_TREE check always uses physical path and not  logical path which may include symlinks.
Fix to ensure that BUILD_TREE check always uses physical path and not 
logical path which may include symlinks.


svn path=/trunk/; revision=8054

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