ocamlfind ocamlopt -package oclock,xml-light2,cdrom,pciutil,sexpr,log,stunnel,http-svr,xen-utils,netdev,tapctl,rpclib,nbd.unix,xenstore-compat,xenctrl,uuid,gzip,libvhd,sha1,xenctrl,xenctrlext,xenstore-compat,cpuid -g -dtypes -thread -warn-error +a-4-6-9-27-28-29 -ccopt -fPIC -I ../idl -I ../idl/ocaml_backend -I ../autogen -I ../database/ -I ../xenops -I ../xva -I ../util -I ../auth -I ../license -I ../client_records -I ../rfb -I ../gpg -I ../network -I ../rrdd/interface -I .. -o sparse_dd.opt ../fhs.cmxa ../util/version.cmxa ../util/vm_memory_constraints.cmxa ../util/sanitycheck.cmxa ../util/stats.cmxa ../idl/ocaml_backend/common.cmxa ../idl/ocaml_backend/client.cmxa ../idl/ocaml_backend/server.cmxa ../util/ocamltest.cmxa ../xenops/xenops_client.cmxa /root/.opam/4.00.1/lib/libvhd/libvhd.cmxa ../auth/pam.cmxa sparse_encoding.cmx ../util/stats.cmx sparse_dd.cmx -cclib -L/usr/lib64 -linkpkg

/root/.opam/4.00.1/lib/libvhd/liblibvhd_stubs.a(vhd_stubs.o): In function `stub_vhd_open':
vhd_stubs.c:(.text+0x161): undefined reference to `vhd_open'