you will need:
ndk r6
run the getvtk.sh script, or download and unzip VTK release 5.6.1 somewhere.
then from this directory:
mkdir build
cd build
cmake-gui ..
make
As part of the cmake-gui step, select the VTK root directory ( if its different ), and the android-ndk path.
you may want to set j to 16 or something.