Simple:

• edit build.properties in your home or j-t-c/jk
• make sure httpd-devel is installed
• Add: apache2.home=/usr 
• Add: apr.include=/usr/include/httpd
• cd j-t-c/jk/native2
• ant

j-t-c/jk/build/jk2/jni/libjkjni.so should be copied to /usr/lib