add forward compatibility with MT 5 for the ancient nodeupdate(pos)

* replace if the new minetest api is detected the `nodeupdate(pos)`
  with the new `check_for_falling(pos)` api since 5.0 but mantains
  backguard compatibility with 4.0.13 to 4.0.16
* use the new expose version check flags from `adventuretest` mod
  so the fire n doors mods must depends on default or adventuretest
* add to respective notes such change

NOTES.md

@@ -5,6 +5,7 @@
 There are the issues Tignasse Verte mentionned: Adding `placer` in `register_functions.lua` 
 (related commit for minenux are commit a996d5ac709446322d6c6261c21e5f0752a6aeeb )
 and replacing the two occourances of `nodeupdate` with `minetest.check_for_falling`.
+(relatd commit for minenux are commit 8c53cabfce2d079df76e57b27b020e016837e8fc )
 
 Other changes are necessary because I changed (and had to change) quite a lot 
 in `mg_villages` internally recently. If you want to get further with running 
@@ -28,61 +29,6 @@ Mobs will likely not work very well. A lot changed regarding them.
 They certainly could use an update as well - as could the goblins. I'm sure the witches 
 from the same modder would feel welcome in the AdventureTest universe, too.
 
-###### now the changes in fact:
-
-DFeniks wrote:
-2020-01-07 10:02:08: ERROR[Main]: ServerError: AsyncErr: Lua: finishGenRuntime error from mod 'default' in callback item_OnPlace(): ...enturetest/mods/adventuretest/register_functions.lua:101: attempt to index local 'placer' (a nil value)
-
-Reason on server-side :
-
-Here are the changes made on server-side, concerning item_OnPlace, for the 5.X.X :
-https://dev.minetest.net/Changelog,
-0.4.16 → 5.0.0 , Released March 4th 2019 / Server-side / User interface / Items
-
-Set placer to nil instead of a non-functional one in item_OnPlace (DTA7)
-Here is why, you may have a nil placer. One issue had been logged :
-https://github.com/minetest/minetest/issues/6487
-place_node crashes the game because of nil player #6487
-
-Here is the commit corresponding :
-https://github.com/minetest/minetest_game/pull/1907/commits/73c5339adb8ff93328f5439bf842767b71e0ce6c
-Add nil checks for placer #1907
-
-Reason in the mod :
-For Adventure Test, in `dungeons.lua`, you have line 33 a `minetest.register_on_generated()`, 
-in it, you have, line 161, a call of `minetest.place_node()`.
-
-In `register_functions.lua`, you have a `minetest.register_on_placenode(adventuretest_placenode)`, 
-so the call of `place_node()` redirect to `adventuretest_placenode()`.
-In the commit, I have found an example of change (a nil check) that can be done 
-in `adventuretest_placenode()`.
-
-What to do :
-Go to :
-games\adventuretest\mods\adventuretest
-There, change the file :
-`register_functions.lua` replace the line 101 (`if placer:is_player() then`) with :
-
-```
-if placer and placer:is_player() then
-```
-
-0.4.16 → 5.0.0 :
-`nodeupdate()` was removed. Fix: replace with `minetest.check_for_falling`.
-
-In Adventuretest I have found 2 calls of `nodeupdate()` (may be there is more).
-When it have been called, I got a crash :
-`AsyncErr: ServerThread::run Lua: Runtime error from mod 'default' in callback LuaABM::trigger(): ...32\bin\..\games\adventuretest\mods\default/functions.lua:385: attempt to call global 'nodeupdate' (a nil value)`
-
-What to do :
-Change the file
-`games\adventuretest\mods\default\functions.lua`
-replace the line 385 (nodeupdate(p0)) with :
-`minetest.check_for_falling(p0)`
-
-Then, change the file `games\adventuretest\mods\doors\init.lua` replace the line 374 with :
-`minetest.check_for_falling({x = pos.x, y = pos.y + 1, z = pos.z})`
-
 ### Fiel of view for monsters vs characters
 
 From https://forum.minetest.net/viewtopic.php?p=182737#p182737

mods/default/functions.lua

@@ -382,7 +382,11 @@ minetest.register_abm({
 			end
 			-- Remove node
 			minetest.remove_node(p0)
-			nodeupdate(p0)
+			if adventuretest.is_50 then
+				minetest.check_for_falling(p0)
+			else
+				nodeupdate(p0)
+			end
 		end
 	end
 })

mods/doors/init.lua

@@ -371,7 +371,11 @@ function doors.register(name, def)
 	end
 	def.after_dig_node = function(pos, node, meta, digger)
 		minetest.remove_node({x = pos.x, y = pos.y + 1, z = pos.z})
-		nodeupdate({x = pos.x, y = pos.y + 1, z = pos.z})
+		if adventuretest.is_50 then
+			minetest.check_for_falling({x = pos.x, y = pos.y + 1, z = pos.z})
+		else
+			nodeupdate({x = pos.x, y = pos.y + 1, z = pos.z})
+		end
 	end
 	def.can_dig = function(pos, player)
 		return can_dig(pos, player)

mods/fire/init.lua

@@ -239,7 +239,11 @@ else
 				local p = minetest.find_node_near(p0, 1, {"group:flammable"})
 				if p then
 					minetest.remove_node(p)
-					nodeupdate(p)
+					if adventuretest.is_50 then
+						minetest.check_for_falling(p)
+					else
+						nodeupdate(p)
+					end
 				end
 			end
 		end,