problems compiling advi into bytecode without -custom

[Ralf Treinen <treinen@free.fr>]

Hello,

I am just working on updating the advi package to the new upstream version
1.8 and encountered a problem with compiling into bytecode. I tried to
remove the "-custom" flag, but that makes compilation fail, with:

  File "_none_", line 1, characters 0-1:
  Error: Error while linking graphicsY11.cmo:
  The external function `caml_gr_unset_cursor' is not available

While it compiles fine when I leave he original -custom flag. Any ideas
what is going on here? Missing compiler flags? A bug in the camlimages
package? Something else?

To reproduce, fetch the advi tree from our git repository, and go into the
branch experimental. Then, add in the file debian/patches/series the
line "byte-compilation-no-custom" (the patch itself is already there),
quilt push -a, and compile with "fakeroot debian/rules build". The 
bytecode executable is produced also on native archs, so you do not
have to hide your /usr/bin/ocamlopt.

Any help will be appreciated -Ralf.