Add C_sources to Dir_contents
Add C_sources to Dir_contents

Signed-off-by: Rudi Grinberg <4c46c202a3b8207ad5740134b125aae40c6c67a8@gmail.com>

janestreet/jbuilder,dra27/jbuilder,dra27/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder