Can't build vpnkit following the instructions

Hi! I use macOS Sierra. Installed opal and wget. Trying to build vpnkit I receive the following (what should I do to build it?):

➜  vpnkit git:(master) opam install --deps-only slirp                       
The following actions will be performed:
  - install hvsock         0.13.0
  - install datakit-server 0.9.0 
  - install dns-forward    0.8.1 
===== 3 to install =====
Do you want to continue ? [Y/n] Y

=-=- Gathering sources =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

=-=- Processing actions -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[ERROR] The compilation of dns-forward failed at "ocaml pkg/pkg.ml build --pinned false".
[ERROR] The compilation of datakit-server failed at "ocaml pkg/pkg.ml build --pinned false -n datakit-server".
[ERROR] The compilation of hvsock failed at "make".
Processing  3/3: [hvsock: ocamlfind remove]
#=== ERROR while installing datakit-server.0.9.0 ==============================#
# opam-version 1.2.2
# os           darwin
# command      ocaml pkg/pkg.ml build --pinned false -n datakit-server
# path         /Users/os/.opam/system/build/datakit-server.0.9.0
# compiler     system (4.04.0)
# exit-code    1
# env-file     /Users/os/.opam/system/build/datakit-server.0.9.0/datakit-server-57805-1872ec.env
# stdout-file  /Users/os/.opam/system/build/datakit-server.0.9.0/datakit-server-57805-1872ec.out
# stderr-file  /Users/os/.opam/system/build/datakit-server.0.9.0/datakit-server-57805-1872ec.err
### stdout ###
# [...]
# ocamlfind ocamlopt -shared -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' src/datakit-server/vfs.cmx -o src/datakit-server/vfs.cmxs
# ocamlfind ocamlc -c -g -bin-annot -safe-string -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' -warn-error +1..49-3 -w A-4-41-44 -I src/datakit-server -I src -o src/datakit-server/vfs.cmo src/datakit-server/vfs.ml
# ocamlfind ocamlc -a -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' src/datakit-server/vfs.cmo -o src/datakit-server/vfs.cma
# ocamlfind ocamldep -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' -modules src/datakit-server/fs9p.ml > src/datakit-server/fs9p.ml.depends
# ocamlfind ocamldep -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' -modules src/datakit-server/fs9p.mli > src/datakit-server/fs9p.mli.depends
# ocamlfind ocamlc -c -g -bin-annot -safe-string -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' -warn-error +1..49-3 -w A-4-41-44 -I src/datakit-server -I src -o src/datakit-server/fs9p.cmi src/datakit-server/fs9p.mli
# + ocamlfind ocamlc -c -g -bin-annot -safe-string -package protocol-9p.unix -package 'bytes lwt astring logs result cstruct fmt rresult' -warn-error +1..49-3 -w A-4-41-44 -I src/datakit-server -I src -o src/datakit-server/fs9p.cmi src/datakit-server/fs9p.mli
# File "src/datakit-server/fs9p.mli", line 17, characters 19-30:
# Error: Unbound module V1_LWT
# Command exited with code 2.
### stderr ###
# pkg.ml: [ERROR] cmd ['ocamlbuild' '-use-ocamlfind' '-classic-display' '-tag' 'debug'
# [...]
#      'src/datakit-server/vfs.a' 'src/datakit-server/vfs.cmxs'
#      'src/datakit-server/vfs.cmxa' 'src/datakit-server/vfs.cma'
#      'src/datakit-server/vfs.cmx' 'src/datakit-server/vfs.cmi'
#      'src/datakit-server/vfs.mli' 'src/datakit-server/fs9p.a'
#      'src/datakit-server/fs9p.cmxs' 'src/datakit-server/fs9p.cmxa'
#      'src/datakit-server/fs9p.cma' 'src/datakit-server/fs9p_error.cmx'
#      'src/datakit-server/fs9p_error.cmi' 'src/datakit-server/fs9p_error.mli'
#      'src/datakit-server/fs9p.cmx' 'src/datakit-server/fs9p.cmi'
#      'src/datakit-server/fs9p.mli']: exited with 10


#=== ERROR while installing dns-forward.0.8.1 =================================#
# opam-version 1.2.2
# os           darwin
# command      ocaml pkg/pkg.ml build --pinned false
# path         /Users/os/.opam/system/build/dns-forward.0.8.1
# compiler     system (4.04.0)
# exit-code    1
# env-file     /Users/os/.opam/system/build/dns-forward.0.8.1/dns-forward-57805-c61e7b.env
# stdout-file  /Users/os/.opam/system/build/dns-forward.0.8.1/dns-forward-57805-c61e7b.out
# stderr-file  /Users/os/.opam/system/build/dns-forward.0.8.1/dns-forward-57805-c61e7b.err
### stdout ###
# ocamlfind ocamldep -package 'dns mirage-flow cstruct.lwt channel io-page.unix' -package 'bytes lwt astring logs result cstruct fmt rresult ipaddr' -modules lib/dns_forward.ml > lib/dns_forward.ml.depends
# ocamlfind ocamldep -package ppx_sexp_conv -package 'dns mirage-flow cstruct.lwt channel io-page.unix' -package 'bytes lwt astring logs result cstruct fmt rresult ipaddr' -modules lib/dns_forward.mli > lib/dns_forward.mli.depends
# ocamlfind ocamlc -c -g -bin-annot -safe-string -package ppx_sexp_conv -package 'dns mirage-flow cstruct.lwt channel io-page.unix' -package 'bytes lwt astring logs result cstruct fmt rresult ipaddr' -warn-error +1..49 -w A-3-4-41-44 -I lib -I bin -o lib/dns_forward.cmi lib/dns_forward.mli
# + ocamlfind ocamlc -c -g -bin-annot -safe-string -package ppx_sexp_conv -package 'dns mirage-flow cstruct.lwt channel io-page.unix' -package 'bytes lwt astring logs result cstruct fmt rresult ipaddr' -warn-error +1..49 -w A-3-4-41-44 -I lib -I bin -o lib/dns_forward.cmi lib/dns_forward.mli
# findlib: [WARNING] Interface topdirs.cmi occurs in several directories: /usr/local/lib/ocaml, /usr/local/lib/ocaml/compiler-libs
# File "lib/dns_forward.mli", line 40, characters 12-38:
# Error: Unbound module Mirage_flow_s
# Command exited with code 2.
### stderr ###
# pkg.ml: [ERROR] cmd ['ocamlbuild' '-use-ocamlfind' '-classic-display' '-tag' 'debug'
# [...]
#      'lib/dns_forward_framing.cmx' 'lib/dns_forward_server.cmx'
#      'lib/dns_forward_resolver.cmx' 'lib/dns_forward_rpc.cmx'
#      'lib/dns_forward_free_id.cmx' 'lib/dns_forward_error.cmx'
#      'lib/dns_forward_config.cmx' 'lib/dns_forward.cmx' 'lib/dns_forward.cmi'
#      'lib/dns_forward.mli' 'lib/dns-forward-lwt-unix.a'
#      'lib/dns-forward-lwt-unix.cmxs' 'lib/dns-forward-lwt-unix.cmxa'
#      'lib/dns-forward-lwt-unix.cma' 'lib/dns_forward_lwt_unix.cmx'
#      'lib/dns_forward_lwt_unix.cmi' 'lib/dns_forward_lwt_unix.mli'
#      'bin/main.native']: exited with 10


#=== ERROR while installing hvsock.0.13.0 =====================================#
# opam-version 1.2.2
# os           darwin
# command      make
# path         /Users/os/.opam/system/build/hvsock.0.13.0
# compiler     system (4.04.0)
# exit-code    2
# env-file     /Users/os/.opam/system/build/hvsock.0.13.0/hvsock-57805-a00279.env
# stdout-file  /Users/os/.opam/system/build/hvsock.0.13.0/hvsock-57805-a00279.out
# stderr-file  /Users/os/.opam/system/build/hvsock.0.13.0/hvsock-57805-a00279.err
### stdout ###
# [...]
# /Users/os/.opam/system/bin/ocamlfind ocamldep -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -modules lwt/lwt_hvsock.ml > lwt/lwt_hvsock.ml.depends
# /Users/os/.opam/system/bin/ocamlfind ocamldep -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -modules lwt/flow_lwt_hvsock.mli > lwt/flow_lwt_hvsock.mli.depends
# /Users/os/.opam/system/bin/ocamlfind ocamlc -c -g -annot -bin-annot -thread -I lib -thread -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -I lwt -I lib -o lwt/flow_lwt_hvsock.cmi lwt/flow_lwt_hvsock.mli
# /Users/os/.opam/system/bin/ocamlfind ocamldep -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -modules lwt/flow_lwt_hvsock.ml > lwt/flow_lwt_hvsock.ml.depends
# /Users/os/.opam/system/bin/ocamlfind ocamldep -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -modules lwt/flow_lwt_hvsock_shutdown.mli > lwt/flow_lwt_hvsock_shutdown.mli.depends
# /Users/os/.opam/system/bin/ocamlfind ocamlc -c -g -annot -bin-annot -thread -I lib -thread -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -I lwt -I lib -o lwt/flow_lwt_hvsock_shutdown.cmi lwt/flow_lwt_hvsock_shutdown.mli
# + /Users/os/.opam/system/bin/ocamlfind ocamlc -c -g -annot -bin-annot -thread -I lib -thread -package unix -package threads -package mirage-types.lwt -package mirage-flow -package lwt -package logs -package duration -package cstruct -package bytes -I lwt -I lib -o lwt/flow_lwt_hvsock_shutdown.cmi lwt/flow_lwt_hvsock_shutdown.mli
# File "lwt/flow_lwt_hvsock_shutdown.mli", line 26, characters 10-36:
# Error: Unbound module Mirage_flow_s
# Command exited with code 2.
### stderr ###
# E: Failure("Command ''/Users/os/.opam/system/bin/ocamlbuild' lib/libhvsock_stubs.a lib/dllhvsock_stubs.so lib/hvsock.cma lib/hvsock.cmxa lib/hvsock.a lib/hvsock.cmxs lwt/hvsock_lwt.cma lwt/hvsock_lwt.cmxa lwt/hvsock_lwt.a lwt/hvsock_lwt.cmxs lwt_unix/hvsock_lwt_unix.cma lwt_unix/hvsock_lwt_unix.cmxa lwt_unix/hvsock_lwt_unix.a lwt_unix/hvsock_lwt_unix.cmxs src/hvcat.native lib_test/test.native -use-ocamlfind -tag debug -tag tests' terminated with error code 10")
# make: *** [build] Error 1



=-=- Error report -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
The following actions failed
  - install datakit-server 0.9.0 
  - install dns-forward    0.8.1 
  - install hvsock         0.13.0
No changes have been performed

Start with the documented vpnkit build instructions and reproduce opam install --deps-only slirp on macOS. Investigate the reported failures in datakit-server, dns-forward, and hvsock, especially the missing V1_LWT and Mirage_flow_s modules. Done means the dependencies install successfully and vpnkit builds following the instructions.