Error while building libvyosconfig package for armhf architecture

Hi all,
I am trying to build libvyosconfig debian Jessie package for armhf architecture.
when I was firing the dpkg-builpackage command it requires few dependencies to install.
please see the below output of my command,
root@dev2k18:/usr/src/vyos-build/packages/libvyosconfig# dpkg-buildpackage -b -us -uc
** dpkg-buildpackage: info: source package libvyosconfig0**
** dpkg-buildpackage: info: source version 0.0.1**
** dpkg-buildpackage: info: source distribution unstable**
** dpkg-buildpackage: info: source changed by Daniil Baturin**
** dpkg-buildpackage: info: host architecture armhf**
** dpkg-source --before-build libvyosconfig**
** debian/rules clean**
** dh clean --with quilt**
** dh_testdir**
** dh_auto_clean**
** make[1]: Entering directory ‘/usr/src/vyos-build/packages/libvyosconfig’**
** rm -rf _build**
** make[1]: Leaving directory ‘/usr/src/vyos-build/packages/libvyosconfig’**
** dh_quilt_unpatch**
** No patch removed**
** dh_clean**
** debian/rules build**
** dh build --with quilt**
** dh_testdir**
** dh_quilt_patch**
** No series file found**
** dh_auto_configure**
** debian/rules override_dh_auto_build**
** make[1]: Entering directory ‘/usr/src/vyos-build/packages/libvyosconfig’**
** ./ debian/tmp**
** rm -rf _build**
** ocamlc -g -c stub/init.c**
** mv init.o _build/stub/init.o**
** menhir parser/vyos1x_parser.mly**
** mv parser/ _build/lib**
** mv parser/vyos1x_parser.mli _build/lib**
** ocamlfind opt -o _build/lib/vyos1x_parser.cmi -I _build/lib -package vyconf,ctypes.stubs,ctypes.foreign _build/lib/vyos1x_parser.mli**
** ocamlfind: Package `vyconf’ not found**
** Makefile:91: recipe for target ‘_build/lib/vyos1x_parser.cmi’ failed**
** make: *** [_build/lib/vyos1x_parser.cmi] Error 2**
** debian/rules:9: recipe for target ‘override_dh_auto_build’ failed**
** make[1]: *** [override_dh_auto_build] Error 2**
** make[1]: Leaving directory ‘/usr/src/vyos-build/packages/libvyosconfig’**
** debian/rules:6: recipe for target ‘build’ failed**
** make: *** [build] Error 2**
** dpkg-buildpackage: error: debian/rules build gave error exit status 2**

which drags me to install vyconf package.
but when I am trying to install vyconf package it is showing me some error which I am not able to understand. Please see the below outout,

**root@dev2k18:~/vyconf_10_03_2021# make**

** ocaml -build **
** Finished, 0 targets (0 cached) in 00:00:00.**
** + /root/.opam/4.03.0/bin/ocamlfind ocamldep -package batteries -package fileutils -package lwt -package lwt.unix -package lwt_log -package lwt_ppx -package ocaml-protoc -package ocplib-endian -package pcre -package -package ppx_deriving_yojson -package sha -package toml -package xml-light -package yojson -modules src/config_tree.mli > src/config_tree.mli.depends**
** File “src/config_tree.mli”, line 1:**
** Error: External preprocessor does not produce a valid file**
** Command line: /root/.opam/4.03.0/lib/lwt_ppx/./ppx.exe --as-ppx ‘/tmp/camlppxcb1122’ ‘/tmp/camlppxe33be7’**

** Command exited with code 2.**
** Compilation unsuccessful after building 1 target (0 cached) in 00:00:00.**
** E: Failure(“Command ‘’/root/.opam/4.03.0/bin/ocamlbuild’ src/vyconf.cma src/vyconf.cmxa src/vyconf.a src/vyconf.cmxs src/vyconfd-config.cma src/vyconfd-config.cmxa src/vyconfd-config.a src/vyconfd-config.cmxs src/client.cma src/client.cmxa src/client.a src/client.cmxs src/vyconfd.native src/vycli.native test/vytree_test.native test/reference_tree_test.native test/config_tree_test.native test/vylist_test.native test/value_checker_test.native test/util_test.native test/vyconf_config_test.native test/curly_parser_test.native test/session_test.native test/vytree_load_test.native -tag debug -tag tests’ terminated with error code 10”)**
** Makefile:7: recipe for target ‘build’ failed**
** make: *** [build] Error 1**

Can anyone guide me on this how can I install vyconf, ctypes.stubs,ctypes.foreign packages and get through this error and ultimately able to build libvyosconfig package?
Any help will be much appreciated.

I have gone through this error by downgrading the lwt package from version 4.1.0 to 3.0.0.
but as moving ahead I am facing another error mentioned below,
+ /root/.opam/4.03.0/bin/ocamlfind ocamlc -c -g -annot -bin-annot -strict-sequence -I src -I src -I src -package batteries -package fileutils -package lwt -package lwt.unix -package ocplib-endian -package pcre -package sha -package toml -package xml-light -package yojson -I src -o src/vyconf_config.cmo src/
File “src/”, line 77, characters 12-21:
Error: Unbound value show

Do any one have any idea about how to resolve it?
Any help will be much appreciated.
Thanks in advance.