[MacPorts] #58852: unison @2.51.2_2: problem with ocaml @4.08.1 - build failure

[MacPorts]

#58852: unison @2.51.2_2: problem with ocaml @4.08.1 - build failure
----------------------------+--------------------
 Reporter:  majoc-at-astro  |      Owner:  (none)
     Type:  defect          |     Status:  new
 Priority:  Normal          |  Milestone:
Component:  ports           |    Version:  2.5.4
 Keywords:                  |       Port:  unison
----------------------------+--------------------
 Unison @2.51.2_2, which built OK last week, now fails when built using
 `ocaml @4.08.1`.  Full log enclosed, but here's the punchline:

 {{{
 ocamlopt: system.ml ---> system.cmx
 ocamlopt -g -unsafe-string -I lwt -I ubase -I system -I fsmonitor -I
 fsmonitor/linux -I fsmonitor/windows -I system/generic -I lwt/generic
 -ccopt -mmacosx-version-min=10.12 -I /opt/local/lib/ocaml/site-
 lib/lablgtk2 -c
 /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_net_unison/unison/work/unison-2.51.2/src/system.ml
 File
 "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_net_unison/unison/work/unison-2.51.2/src/system.ml",
 line 1:
 Error: The implementation
 /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_net_unison/unison/work/unison-2.51.2/src/system.ml
        does not match the interface system.cmi:
        Values do not match:
          val link : ?follow:bool -> string -> string -> unit
        is not included in
          val link : fspath -> fspath -> unit
        File
 "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_net_unison/unison/work/unison-2.51.2/src/system/system_intf.ml",
 line 70, characters 0-35:
          Expected declaration
        File
 "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_net_unison/unison/work/unison-2.51.2/src/system/system_generic.ml",
 line 50, characters 4-8:
          Actual declaration
 make[1]: *** [system.cmx] Error 2
 }}}

 macOS: 10.12 (Xcode 9.2), 10.13 (Xcode 9.4.1), 10.14 (Xcode 10.3).

 I don't pretend to understand ocaml, so I won't spoil the kill with
 uninformed speculation.  Please let me know if there's any further
 information that would help.  Thanks in advance.

-- 
Ticket URL: <https://trac.macports.org/ticket/58852>
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