Calculating point distance to hyperplane, LibSVM?

I wasn't sure if anyone had run into an instance when they needed to know the distance from a point to the hyperplane. In the FAQ for for LibSVM they write the following:

Q: How do I get the distance between a point and the hyperplane?

The distance is |decision_value| / |w|. We have |w|² = w^Tw = alpha^T Q alpha = 2*(dual_obj + sum alpha_i). Thus in svm.cpp please find the place where we calculate the dual objective value (i.e., the subroutine Solve()) and add a statement to print w^Tw.

My issue is, I'm using MATLAB. And so I have no idea how to alter the C files and then recompile, or whatever, to use in MATLAB. Wasn't sure if anyone has overcome this issue...Thanks!