I'm trying to compile emacs 28.2 (from https://ftp.gnu.org/gnu/emacs/) with json support on a Ubuntu-based system (Linux Mint). But I don't get it to work meaning that json-available-p is void and I cannot use the json-parse-string function.
I installed the libjansson-dev library and added --with-json as a parameter to configure. It shows Does Emacs use -ljansson? yes. But within emacs the json-support is not working. What else do I need or am I missing something?