Created attachment 1217545 [details]
build.log

Description of problem:

The new OCaml compiler seems to be finding genuine errors in the code
such as:

Error: The implementation /builddir/build/BUILD/unison-2.40.128/system.ml
       does not match the interface system.cmi:
       Values do not match:
         val symlink : ?to_dir:bool -> string -> string -> unit
       is not included in
         val symlink : string -> fspath -> unit

For full details see the attached build log.

http://koji.fedoraproject.org/koji/taskinfo?taskID=16301046

Version-Release number of selected component (if applicable):

unison240-2.40.128-5.fc26

How reproducible:

Once.

Steps to Reproduce:
1. Build the package in Rawhide side tag f26-ocaml