Fix from Phil Rosenberg for compile errors in plplot versions of snprintf and snscanf if the library versions are not available. 
Fix from Phil Rosenberg for compile errors in plplot versions of snprintf and snscanf if the library versions are not available. 


svn path=/trunk/; revision=12858

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