Building and installing from source
If your OS does not yet ship with libreswan packages, your you wish to install the latest version, you can build/install or package libreswan from source yourself.
For OS distributions that use a packaging system, the source archive contains the directory packaging/. This directory provides an easy way to build packages for the current operating system.
Here is simple procedure to build debian package from libreswan tarball.
$ make deb
Building/Installing into /usr/local
Below is an alphabetic list of distributions and how to install from source. As a distro EOLs, it can be removed.
dnf group install 'C Development Tools and Libraries' dnf install make nss-devel libevent-devel unbound-devel bison flex audit-libs-devel libcurl-devel pam-devel libselinux-devel libseccomp-devel systemd-devel libcap-ng-devel ldns-devel xmlto make make install
pkg_add ???? make make install