Make dpdgraph compile again

Unfortunately, it still stack-overflows.  I might need some help from
@mattam82, or I might need to figure out how to actually debug OCaml
code.  I presume I managed to make it loop on primitive projections
somewhere...
Merge pull request #642 from JasonGross/fix-dpd-graph-trunk

Make dpdgraph compile again
./autogen.sh