It fails with this message:

gcj  --encoding=UTF-8 -I"/tmp/SBo/pdftk-1.12/java_libs" -c PngImage.java -o 
PngImage.o
PngImage.java: In class 'com.lowagie.text.pdf.codec.PngImage':
PngImage.java: In method 'com.lowagie.text.pdf.codec.PngImage.getImage()':
PngImage.java:568: error: Class 'ImgRaw' not found in type declaration.
                img = new ImgRaw(width, height, components, bpc, 
idat.toByteArray());
                             ^
1 error
make[2]: *** [PngImage.o] Error 1
make[2]: Leaving directory 
`/tmp/SBo/pdftk-1.12/java_libs/com/lowagie/text/pdf/codec'
make[1]: *** [itext] Error 2
make[1]: Leaving directory `/tmp/SBo/pdftk-1.12/java_libs'
make: *** [java_libs] Error 2