e (i.e., zlib) encoding.  PDF will
   also wrap jpeg2000 images.

   There is a programmatic interface to gnuplot.  To use it, you
   need only the gnuplot executable (suggest version 3.7.2 or later);
   the gnuplot library is not required.

   If you build with automake, libraries on your system will be
   automatically found and used.

   The rest of this section is for building with the static makefiles.
   The entries in environ.h specify which of these libraries to use.
   The default is to link to the