remove lablgtk references to macOS install instructions
Fixes frama-c#2655 (closed) (not tested)
Should we also add a why3 config detect
step as mentioned in the issue? It is not present in the Linux instructions (nor the WSL ones), and as far as I can tell, the idea is to keep these instructions short and refer to the full INSTALL.md
for detailed information.
Edited by Virgile Prevosto