Moved #ifdef PLD_gnome higher so this doesn't break the build on other platforms, and included plplot/drivers.h to get the driver API prototypes.
Moved #ifdef PLD_gnome higher so this doesn't break the build on other
platforms, and included plplot/drivers.h to get the driver API prototypes.

svn path=/trunk/; revision=2840

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