I was unsuccessful compiling PPPD 2.2.0c on my 1.2.13 machines. I compiled
1.3.35 on the machines and used PPDP with it. Just follow the instructions
in README.linux included in ppp-2.2.0c and all should work.
Hope this helps people who are having trouble - also I've found the 1.3.35
kernel's to be quite stable.