I started a clean Ubuntu 20.04 on my virtualbox and installed janus-gateaway without errors using sequence of commands:
root@test-janus:~# apt-get update -y ; apt-get upgrade -y ; apt-get install apt-utils -y
root@test-janus:~# apt-get install -y libmicrohttpd-dev libjansson-dev libssl-dev libsofia-sip-ua-dev libglib2.0-dev libopus-dev libogg-dev libusrsctp1 libusrsctp-dev libcurl4-openssl-dev liblua5.3-dev libconfig-dev pkg-config gengetopt libtool automake autoconf cmake gtk-doc-tools libini-config-dev libcollection-dev autotools-dev make git doxygen graphviz ffmpeg python3-pip sudo
root@test-janus:~# mkdir janus-build
root@test-janus:~# cd janus-build
root@test-janus:~/janus-build# git clone
https://libwebsockets.org/repo/libwebsocketsroot@test-janus:~/janus-build# cd libwebsockets
root@test-janus:~/janus-build/libwebsockets# git checkout v3.2.0
root@test-janus:~/janus-build/libwebsockets# mkdir build
root@test-janus:~/janus-build/libwebsockets# cd build
root@test-janus:~/janus-build/libwebsockets/build# cmake -DLWS_MAX_SMP=1 -DCMAKE_INSTALL_PREFIX:PATH=/usr -DCMAKE_C_FLAGS="-fpic" ..
root@test-janus:~/janus-build/libwebsockets/build# make && sudo make install
root@test-janus:~/janus-build/libwebsockets/build# cd ../..
root@test-janus:~/janus-build# pip3 install meson ninja
root@test-janus:~/janus-build# git clone
https://gitlab.freedesktop.org/libnice/libniceroot@test-janus:~/janus-build# cd libnice
root@test-janus:~/janus-build/libnice# meson --prefix=/usr build && ninja -C build && sudo ninja -C build install
root@test-janus:~/janus-build/libnice# cd ..
root@test-janus:~/janus-build# wget
https://github.com/cisco/libsrtp/archive/v2.2.0.tar.gzroot@test-janus:~/janus-build# tar xfv v2.2.0.tar.gz
root@test-janus:~/janus-build# cd libsrtp-2.2.0
root@test-janus:~/janus-build/libsrtp-2.2.0# ./configure --prefix=/usr --enable-openssl
root@test-janus:~/janus-build/libsrtp-2.2.0# make shared_library && sudo make install
root@test-janus:~/janus-build/libsrtp-2.2.0# cd ..
root@test-janus:~/janus-build# git clone
https://github.com/meetecho/janus-gateway.gitroot@test-janus:~/janus-build# cd janus-gateway
root@test-janus:~/janus-build/janus-gateway# sh autogen.sh
root@test-janus:~/janus-build/janus-gateway# ./configure --prefix=/opt/janus
root@test-janus:~/janus-build/janus-gateway# make
root@test-janus:~/janus-build/janus-gateway# make install
root@test-janus:~/janus-build/janus-gateway# cd /opt/janus/bin
root@test-janus:/opt/janus/bin# ./janus --version
Janus commit: 16e2cc310c6081c645b63b1cc9dbb80b8d55ff26
Compiled on: Fri 25 Jun 2021 12:25:32 PM UTC
janus 0.11.4
root@test-janus:/opt/janus/bin#