This works through a new field "touch_interaction" in item definitions.
The two most important use cases are:
- Punching players/entities with short tap instead of long tap (enabled by default)
- Making items usable that require holding the place button (e.g. bows and shields in MC-like games)
On the lua side, notably minetest.env:<function>(<args>) should now
be replaced by minetest.<function>(<args>).
The old way is and will stay supported for a long time.
Also:
Update and clean up lua_api.txt (by celeron55)
Move EnvRef to lua and remove add_rat and add_firefly (by kahrl)
Add separate src/util/CMakeLists.txt, other minor fixes (by kahrl)