ocaml-dune build error: error: 'COPYFILE_CLONE' undeclared (first use in this function); did you mean 'COPYFILE_MOVE'?

[barracuda156]

Any idea why this may be happening? Both dune 3.11.0 and 3.11.1 fail.

--->  Building ocaml-dune
Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_ocaml_ocaml-dune/ocaml-dune/work/dune-3.11.0" && /usr/bin/make -j6 -w release 
make: Entering directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_ocaml_ocaml-dune/ocaml-dune/work/dune-3.11.0'
ocamlc -output-complete-exe -w -24 -g -o .duneboot.exe -I boot unix.cma boot/libs.ml boot/duneboot.ml
./.duneboot.exe
cd _boot && /opt/local/bin/ocamlc -c -g -I +threads copyfile_stubs.c
otherlibs/stdune/src/copyfile_stubs.c: In function 'stdune_copyfile':
otherlibs/stdune/src/copyfile_stubs.c:45:39: error: 'COPYFILE_CLONE' undeclared (first use in this function); did you mean 'COPYFILE_MOVE'?
otherlibs/stdune/src/copyfile_stubs.c:45:39: note: each undeclared identifier is reported only once for each function it appears in
make: *** [_boot/dune.exe] Error 2
make: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_ocaml_ocaml-dune/ocaml-dune/work/dune-3.11.0'

[barracuda156]

In 0c68154e8b71366705a3df02376b0934eb1f7fae/macports-ports (master):

ocaml-dune: update to 3.11.1, fix for old systems

Fixes: #68463