I'm sorry, where does apt-get fit into the picture ?
lwjgl is purely ant based when compiling, except for the native part which assumes you have the dependencies installed.
For the debug jar you need only compile the java stuff:
svn co https://java-game-lib.svn.sourceforge.net/svnroot/java-game-lib/trunk/LWJGL lwjgl
cd lwjgl
mkdir bin
<edit platform_build/build-generator.xml>
ant jars