Here are some minimal Ubuntu 22.04 installation instructions.

[compoundradius]

Minimal Ubuntu 22.04 installation instructions.

git clone https://github.com/akheron/jansson && \
cd jansson  && \
autoreconf -i && \
./configure && \
make && \
sudo make install

# OpenSSL > 3.0 will show these as errors
# jws.c:446:5: warning: ‘RSA_size’ is deprecated: Since OpenSSL 3.0 [-Wdeprecated-declarations]
# so pass --disable-werror

git clone https://github.com/cisco/cjose.git && \
cd cjose && \
./configure --disable-werror --with-openssl=/usr/local --with-jansson=/usr/local && \
sudo make install

# There did not seem to be a way to disable
# configure: error: "apxs not found. Use --with-apxs"
# without first installing the following package:
sudo apt install apache2-dev

git clone https://github.com/OpenIDC/liboauth2 && \
cd liboauth2 && \
./autogen.sh && \
./configure && \
make && \
sudo make install

[zandbelt]

installation on Ubuntu/Debian/CentOS is better done with the binaries provided with each release from here https://github.com/OpenIDC/liboauth2/releases and cjose from here https://github.com/OpenIDC/cjose/releases

[compoundradius]

It would be helpful if you then updated the cjose link in README.md to the new location:
https://github.com/cisco/cjose -> https://github.com/OpenIDC/liboauth2/releases
Thanks!