scoding whenever possible.
     * prog/convertfilestopdf.c: more flexibility in the output.  You
       can set the resolution, scaling, encoding type and jpeg quality.
     * prog/convertsegfilestopdf.c: generates a multipage, mixed raster pdf,
       with separate controls for compressing text and non-text regions.

   Note: any or all of these I/O library calls can be stubbed out at
         compile time, using the environment variables in environ.h.

   For all formatted reads and writes, we support rea