Unpack the source and run 3 times make.
The las time you run make
you get some errors going like this:
(your could be different)
...
.../libpng.so: undefined reference to `deflate'
.../libpng.so: undefined reference to `inflate'
.../libpng.so: undefined reference to `inflateInit_'
.../libpng.so: undefined reference to `crc32'
.../libpng.so: undefined reference to `deflateInit2_'
.../libpng.so: undefined reference to `inflateReset'
.../libpng.so: undefined reference to `deflateReset'
.../libpng.so: undefined reference to `inflateEnd'
.../libpng.so: undefined reference to `deflateEnd'
...
Now open the file Makefile and edit the line
which contains the following:
$(LINK.o) $^ -L/usr/local/lib -lstdc++ -lpng -o $@
Change it now to the following:
$(LINK.o) $^ -L/usr/local/lib -lstdc++ -lpng -lz -o $@
Here we add -lz to link agains the Zlib.
Save and exit.
Run make once again.
Done.
Extras

Save this script in an executable file and run it to have
PNGs from all the files in the input directory.
#!/bin/sh
for i in input/*
do
./cfdg -s 500 $i $i.png
done;
This is what worked for me. Your mileage may vary.
Ragards