Change in plbuf.c so that the pattern is only set via c_plpat if the number of lines is not equal to 0. This avoids warnings.
Change in plbuf.c so that the pattern is only set via c_plpat if the number of lines is not equal
to 0. This avoids warnings.

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