Be more careful of the case (e.g., FORCE_EXTERNAL_STATIC ON) when wxwidgets libraries are not found.
Be more careful of the case (e.g., FORCE_EXTERNAL_STATIC ON) when
wxwidgets libraries are not found.

svn path=/trunk/; revision=12065

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