%check section fails if ocaml-perl4caml has been installed.
The explanation for this is in the spec file:

  %check
  # This fails if perl4caml is installed.  The bytecode programs
  # load dllperl4caml.so from OCaml's stublibs, instead of the
  # one we just built.  Since dllperl4caml.so in stublibs
  # (wrongly) lacks an rpath for libperl.so, it won't find
  # libperl.so in the obscure directory where it resides.
  # Monkeying around with LD_LIBRARY_PATH doesn't help because
  # ocamlrun uses $libdir/ocaml/ld.conf to find directories
  # containing the stublibs.
  make test ||:

It should be possible to fix this by setting an environment
variable such as CAML_LD_LIBRARY_PATH.  See section 10.3
of the manual:

  http://caml.inria.fr/pub/docs/manual-ocaml/manual024.html