move c2hs under grandfathered packages (#5633)
move c2hs under grandfathered packages (#5633)

iand675/stackage,massysett/stackage,soenkehahn/stackage,simonmichael/stackage,fpco/stackage,clinty/stackage,mrkkrp/stackage,jonschoning/stackage,michalkonecny/stackage,Daniel-Diaz/stackage