How to use Cilly on Mac:
- you need to install ocaml and cil
- you need to install frama-c

Find the libc path of Frama-c using:

frama-c -print-share-path

for me this is /usr/local/share/frama-c

Then run cilly using the frama-c version of libc:

cilly --dosimpleMem --dosimplify  --domakeCFG  --save-temps -g -O0  -I/usr/local/share/frama-c/libc sed.c

note that you have to add /libc to the frama-c share path.
NOTE that this will terminate with a link error! 
But you get a file called sed.cil.c
