* For some unexplained reason, `mcl_burning.storage[player]` can
sometimes be `nil`, causing a crash in `on_leaveplayer()`. This
commit adds a check for that. If a `nil` is encountered, a sane
value is substituted and a warning is set to the log.
* Change carpet from `group:attached_node` to `group:supported_node`,
allowing carpets to be placed on top of torches, water source blocks
and other non-walkable nodes, like in MC.
* Add support for `group:supported_node` to CORE/mcl_attached.
Supported nodes are nodes that can be placed on any node that does not
have the `drawtype = "airlike"` attribute.
* Copy the `drop_attached_node()` function from minetest/builtin, so
that the override function provides the same behavior when nodes drop.
* Add comments to CORE/mcl_attached and to the functions defined in it.
* Add more local aliases for global minetest.* functions.
* If the original function returns true, it is not necessary anymore
to perform more tests and the override function can simply return true
immediately.
* Remove unused code that was commented out. The code tried to find
fire luaentities in the same spot as the newly created fire luaentity.
It may have been intended to optimize getting set on fire multiple
times, but it makes no sense as it does not discriminate between fire
luaentities attached to the object set on fire and those attached to
other objects. The function that this code was in also has a better
way to prevent adding multiple fire luaentities in the first place.
* In mineclone5 a crash was reported to occur when deserialization of
storage returned nil in on_joinplayer. https://git.minetest.land/
MineClone5/MineClone5/commit/96c4fb60d8641b4181edb902ed24dbf173828d09
This commit uses a different, but equally effective fix.
* Remove animation_frame from fire entity state, it is now kept in the
storage table of the parent entity.
* Rename animation_timer in fire entity table to _mcl_animation_timer,
in line with mineclone2 policy on adding custom members to minetest
tables.
* Comment out code that does nothing sensible. Scheduled for deletion
at a later time.
