如何编译需要更新版glib的程序

I am trying to compile Webkit on Ubuntu 8.04. But when i run autogen.sh, I get the following error saying it needs a newer version of glib. So what is the safest way to install glib without screwing up the rest of my OS (since the rest needs 2.16 while webkit compile needs 2.21)?I am trying to compile Webkit on Ubuntu 8.04. B