As an alternative to using a prebuilt GHDL version, I wanted to build it from source.
I cloned the repo from GitHub, as
git clone https://github.com/ghdl/ghdl.git Following the instructions on the GitHub page, I started with getting an Ada compiler.
I downloaded and ran an installer for Mac, from the AdaCore site.
The installed Gnat Ada compiler was installed in
$HOME/opt/GNAT/2020 In the ghdl repo, I now set up the PATH, by adding the Gnat Ada compiler directory at the end (I noted that adding it at the front led to the gcc inside Gnat Ada being picked up by mistake when building GHDL), as