cvs diff -u --show-c-function \
 | sed -e "/^Index: /s/$/      {{{1/" \
 | sed -e "/^@@ /s/$/   {{{2/" \
 | gvim "+set fdm=marker" "+set fdl=0" "+set syntax=diff" -
# add "+set fdc=3" to the line above if you want to be able to use a mouse click
# to unfold the changes in each file.