Allow wxWidgets_DEFINITIONS to be a blank-delimited string (cmake 2.4.8) or a list (cmake cvs version).
Allow wxWidgets_DEFINITIONS to be a blank-delimited string (cmake 2.4.8) or
a list (cmake cvs version).

svn path=/trunk/; revision=8321

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