libmd seems to have been introduced for fc35 and later … is there any RPM repo to install it from on FC34, or is build from source the only realistic option?
You may be able to install it from the F35 repo with a properly structured dnf install command. However, since it probably has dependencies that did not exist with F34 it may be a bit tricky to do so without breaking your OS.
Why would you want to do so with a fedora release that is already more than 6 months past EOL when it is very simple to upgrade the entire OS release version and enable installing the package directly with no risk of corrupting the running OS?