lablgtk and OCaml-64 Mac OS X Intel

Hello all,

with release 3.11.0, the amd64 instruction set
became supported by OCaml for Mac OS X Intel.
Use ./configure -cc "gcc -m64" before the bootstrap
to compile a 64-bit OCaml.

However, I have not gotten lablgtk 2.12.0 to compile
(although the same version compiles and works
fine with 32-bit OCaml on Mac OS X Intel).
"make" in lablgtk-2.12.0 ends in:
ocamlmktop  -thread  -o lablgtktop unix.cma threads.cma  \
	   -I . lablgtk.cma lablglade.cma lablgnomecanvas.cma lablgtksourceview.cma gtkThread.cmo
File "_none_", line 1, characters 0-1:
Error: Error on dynamically loaded library: ./dlllablgtk2.so: dlopen(./dlllablgtk2.so, 138): Symbol not found: _gtk_major_version
  Referenced from: /Users/pascal/lablgtk-2.12.0/src/dlllablgtk2.so
  Expected in: flat namespace

make[1]: *** [lablgtktop] Error 2
make: *** [all] Error 2

Did anyone succeed in compiling lablgtk for
Ocaml-64 for Mac OS X Intel ?

Pascal