How to build LibGDX from source?

Question

I am trying hard to build LibGDX from sources (with ANT). I have some minor changes in the native code. I only need compilation for Android.

Theoretically, I've finally managed to compile my C++ files, by switching to Ubuntu (on Windows ANT did not even try to compile). I made some minor changes in .java files. I then ran main Build.xml - the one that builds the jars, and open resultant gdx-setup.jar. Everything installed fine, new projects for eclipse were created.

But my changes were not applied. Auto-completion did not see anything. I also couldn't run the app - java complained, that it couldn't find MyGameClass, even if it was clearly in the core project. Funny thing is, the same exception will come up even when I do not modify anything.

This makes me think, that despite my two days' effort, I still do everything wrong. How should I do it?