Example files compilation throws error

[tanim-ics]

I am following the ndn-iot-package-over-posix documentation. After cloning the repo, I have created a directory named "build",
and from the build folder I have executed the command cmake -DCMAKE_BUILD_TYPE=Release .. Everything was working ok.
but after this when I am executing make -j`nproc` it starts throwing error. It would be a great help if you could guide me in the right direction. I am sharing the output of my terminal.

root@1afe2012cd7e:~# git clone --recursive https://github.com/named-data-iot/ndn-iot-package-over-posix.git
Cloning into 'ndn-iot-package-over-posix'...
remote: Enumerating objects: 1353, done.
remote: Counting objects: 100% (65/65), done.
remote: Compressing objects: 100% (50/50), done.
remote: Total 1353 (delta 35), reused 34 (delta 15), pack-reused 1288
Receiving objects: 100% (1353/1353), 544.58 KiB | 2.62 MiB/s, done.
Resolving deltas: 100% (870/870), done.
Submodule 'ndn-lite' (https://github.com/named-data-iot/ndn-lite.git) registered for path 'ndn-lite'
Cloning into '/root/ndn-iot-package-over-posix/ndn-lite'...
remote: Enumerating objects: 5457, done.
remote: Counting objects: 100% (55/55), done.
remote: Compressing objects: 100% (40/40), done.
remote: Total 5457 (delta 24), reused 29 (delta 15), pack-reused 5402
Receiving objects: 100% (5457/5457), 1.87 MiB | 2.69 MiB/s, done.
Resolving deltas: 100% (3869/3869), done.
Submodule path 'ndn-lite': checked out '287909311e37baea2ee50b38678e5ff309c82a1f'
root@1afe2012cd7e:~# cd ndn-iot-package-over-posix/
root@1afe2012cd7e:~/ndn-iot-package-over-posix# ls
CMakeInputs     QR_encoder.py  adaptation  devices  examples     ndn-lite    tutorial_shared_info.txt
CMakeLists.txt  README.rst     benchmarks  docs     legacy-docs  ndn-lite.h  wrapper
root@1afe2012cd7e:~/ndn-iot-package-over-posix# mkdir build
root@1afe2012cd7e:~/ndn-iot-package-over-posix# cd build/
root@1afe2012cd7e:~/ndn-iot-package-over-posix/build# cmake -DCMAKE_BUILD_TYPE=Release ..
-- The C compiler identification is GNU 9.3.0
-- The CXX compiler identification is GNU 9.3.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)
Documentation skipped
-- Configuring done
-- Generating done
-- Build files have been written to: /root/ndn-iot-package-over-posix/build
root@1afe2012cd7e:~/ndn-iot-package-over-posix/build# make -j`nproc`
Scanning dependencies of target ndn-lite
[  1%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/access-control.c.o
[  2%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/security-bootstrapping.c.o
[  5%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/ndn-sig-verifier.c.o
[  5%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/service-discovery.c.o
[  6%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/pub-sub.c.o
[  7%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/policy.c.o
[  9%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/repo.c.o
[ 10%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/app-support/ndn-trust-schema.c.o
[ 11%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/data.c.o
[ 13%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/encrypted-payload.c.o
[ 14%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/interest.c.o
[ 15%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/key-storage.c.o
[ 17%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/metainfo.c.o
[ 18%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/name-component.c.o
[ 19%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/name.c.o
[ 21%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/signature.c.o
[ 22%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/signed-interest.c.o
[ 23%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/forwarder-helper.c.o
[ 25%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/ndn-rule-storage.c.o
[ 26%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/wrapper-api.c.o
[ 27%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/trust-schema/ndn-trust-schema-pattern-component.c.o
[ 28%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/trust-schema/ndn-trust-schema-pattern.c.o
[ 30%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/encode/trust-schema/ndn-trust-schema-rule.c.o
[ 31%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/face/dummy-face.c.o
[ 32%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/forwarder/face-table.c.o
[ 34%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/forwarder/fib.c.o
[ 35%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/forwarder/forwarder.c.o
[ 36%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/forwarder/name-tree.c.o
[ 38%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/forwarder/pit.c.o
[ 39%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/util/memory-pool.c.o
[ 40%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/util/msg-queue.c.o
[ 42%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/util/re.c.o
[ 43%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-ecc.c.o
[ 44%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-aes.c.o
[ 46%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-hmac.c.o
[ 47%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-rng.c.o
[ 48%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-sec-config.c.o
[ 51%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-sec-utils.c.o
[ 51%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/ndn-lite-sha.c.o
[ 52%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/ndn-lite-default-aes-impl.c.o
[ 53%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/ndn-lite-default-ecc-impl.c.o
[ 55%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/ndn-lite-default-rng-impl.c.o
[ 56%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/ndn-lite-default-hmac-impl.c.o
[ 57%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/ndn-lite-default-sha-impl.c.o
[ 59%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/micro-ecc/uECC.c.o
[ 60%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_aes_decrypt.c.o
[ 61%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_aes_encrypt.c.o
[ 63%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_cbc_mode.c.o
[ 64%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ccm_mode.c.o
[ 65%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_cmac_mode.c.o
[ 67%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ctr_mode.c.o
[ 68%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ctr_prng.c.o
[ 69%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ecc_dh.c.o
[ 71%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ecc_dsa.c.o
[ 73%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ecc_platform_specific.c.o
[ 73%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_ecc.c.o
[ 75%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_hmac_prng.c.o
[ 76%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_hmac.c.o
[ 77%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_sha256.c.o
[ 78%] Building C object CMakeFiles/ndn-lite.dir/ndn-lite/security/default-backend/sec-lib/tinycrypt/tc_utils.c.o
[ 81%] Building C object CMakeFiles/ndn-lite.dir/adaptation/udp/udp-face.c.o
[ 81%] Building C object CMakeFiles/ndn-lite.dir/adaptation/uniform-time.c.o
[ 82%] Building C object CMakeFiles/ndn-lite.dir/adaptation/unix-socket/unix-face.c.o
[ 84%] Building C object CMakeFiles/ndn-lite.dir/adaptation/security/ndn-lite-rng-posix-crypto-impl.c.o
[ 85%] Building C object CMakeFiles/ndn-lite.dir/adaptation/ndn-lite.c.o
[ 86%] Linking C static library libndn-lite.a
[ 86%] Built target ndn-lite
Scanning dependencies of target tutorial-app-sub
Scanning dependencies of target test-repo
Scanning dependencies of target app-template
Scanning dependencies of target tutorial-app
[ 88%] Building C object CMakeFiles/tutorial-app-sub.dir/examples/tutorial-app-sub.c.o
[ 92%] Building C object CMakeFiles/test-repo.dir/examples/test-repo.c.o
[ 92%] Building C object CMakeFiles/tutorial-app.dir/examples/tutorial-app.c.o
[ 92%] Building C object CMakeFiles/app-template.dir/examples/app-template.c.o
/root/ndn-iot-package-over-posix/examples/tutorial-app-sub.c: In function 'load_bootstrapping_info':
/root/ndn-iot-package-over-posix/examples/tutorial-app-sub.c:73:5: error: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Werror=unused-result]
   73 |     fgets(buf, sizeof(buf), fp);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/root/ndn-iot-package-over-posix/examples/app-template.c: In function 'load_bootstrapping_info':
/root/ndn-iot-package-over-posix/examples/app-template.c:63:5: error: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Werror=unused-result]
   63 |     fgets(buf, sizeof(buf), fp);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/root/ndn-iot-package-over-posix/examples/tutorial-app.c: In function 'load_bootstrapping_info':
/root/ndn-iot-package-over-posix/examples/tutorial-app.c:66:5: error: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Werror=unused-result]
   66 |     fgets(buf, sizeof(buf), fp);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/root/ndn-iot-package-over-posix/examples/test-repo.c: In function 'load_bootstrapping_info':
/root/ndn-iot-package-over-posix/examples/test-repo.c:63:5: error: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Werror=unused-result]
   63 |     fgets(buf, sizeof(buf), fp);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/root/ndn-iot-package-over-posix/examples/app-template.c: At top level:
cc1: error: unrecognized command line option '-Wno-int-to-void-pointer-cast' [-Werror]
cc1: all warnings being treated as errors
make[2]: *** [CMakeFiles/app-template.dir/build.make:63: CMakeFiles/app-template.dir/examples/app-template.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:113: CMakeFiles/app-template.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
/root/ndn-iot-package-over-posix/examples/tutorial-app-sub.c: At top level:
cc1: error: unrecognized command line option '-Wno-int-to-void-pointer-cast' [-Werror]
cc1: all warnings being treated as errors
make[2]: *** [CMakeFiles/tutorial-app-sub.dir/build.make:63: CMakeFiles/tutorial-app-sub.dir/examples/tutorial-app-sub.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:140: CMakeFiles/tutorial-app-sub.dir/all] Error 2
/root/ndn-iot-package-over-posix/examples/test-repo.c: At top level:
cc1: error: unrecognized command line option '-Wno-int-to-void-pointer-cast' [-Werror]
cc1: all warnings being treated as errors
make[2]: *** [CMakeFiles/test-repo.dir/build.make:63: CMakeFiles/test-repo.dir/examples/test-repo.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:86: CMakeFiles/test-repo.dir/all] Error 2
/root/ndn-iot-package-over-posix/examples/tutorial-app.c: At top level:
cc1: error: unrecognized command line option '-Wno-int-to-void-pointer-cast' [-Werror]
cc1: all warnings being treated as errors
make[2]: *** [CMakeFiles/tutorial-app.dir/build.make:63: CMakeFiles/tutorial-app.dir/examples/tutorial-app.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:167: CMakeFiles/tutorial-app.dir/all] Error 2
make: *** [Makefile:130: all] Error 2