mtime fails to build with 4.14.0+trunk

[shubhamkumar13]

I get the following error log when I try to build mtime with 4.14.0+trunk and dune.2.9.0

#=== ERROR while compiling mtime.1.2.0 ========================================#
# context     2.0.8 | linux/x86_64 | ocaml-variants.4.14.0+trunk | https://opam.ocaml.org#1fc79772
# path        ~/.opam/4.14.0+trunk/.opam-switch/build/mtime.1.2.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build ocaml pkg/pkg.ml build --pinned false --with-js_of_ocaml false
# exit-code   1
# env-file    ~/.opam/log/mtime-2324156-d2c37b.env
# output-file ~/.opam/log/mtime-2324156-d2c37b.out
### output ###
# [...]
# Command exited with code 2.
# pkg.ml: [ERROR] cmd ['ocamlbuild' '-use-ocamlfind' '-classic-display' '-j' '4' '-tag' 'debug'
#      '-build-dir' '_build' 'opam' 'pkg/META' 'CHANGES.md' 'LICENSE.md'
#      'README.md' 'src/mtime.a' 'src/mtime.cmxs' 'src/mtime.cmxa'
#      'src/mtime.cma' 'src/mtime.cmx' 'src/mtime.cmi' 'src/mtime.mli'
#      'src/mtime_top.a' 'src/mtime_top.cmxs' 'src/mtime_top.cmxa'
#      'src/mtime_top.cma' 'src/mtime_top.cmx' 'src/mtime_top_init.ml'
#      'doc/index.mld' 'src-os/mtime_clock.a' 'src-os/mtime_clock.cmxs'
#      'src-os/mtime_clock.cmxa' 'src-os/mtime_clock.cma'
#      'src-os/mtime_clock.cmx' 'src-os/mtime_clock.cmi'
#      'src-os/mtime_clock.mli' 'src-os/dllmtime_clock_stubs.so'
#      'src-os/libmtime_clock_stubs.a' 'test-os/min_os.ml']: exited with 10

[dbuenzli]

See ocaml/ocaml#10556