Please use https://github.com/computations/lagrange-ng for a fast lagrange or https://github.com/rhr/lagrange-python for the python implementation.
this was the git version of the http://code.google.com/p/lagrange c++ version
this changed from a configure/Makefile project to cmake
to build run
cmake .
make