https://github.com/kac-/peercoin-ce/blob/notes/notes/diff_bitcoin0.6.3-ppcoin0.4.0/main.h.diff
https://github.com/ppcoin/ppcoin/blob/master/src/main.h
to
https://github.com/kac-/peercoin-ce/blob/master/src/main.h

Beside simple merge there is reorganization involved, parts from main.h goes to core.h, functions/members definitions need to be moved to corresponding .cpp files