This command works to get the files and compile them:
git clone a-valid-git-url
for example:
git clone git://cfdem.git.sour
Sometimes its because of ssh. So you can use this:
git clone https://cfdem.git.sourceforge.net/gitroot/cfdem/liggghts
instead of:
git clone git://cfdem.git.sourceforge.net/gitroot/cfdem/liggghts