Minor bitser update (#1353)

Also, jot down the exact commit it was taken from to ease maintenance.

ffi/bitser.lua

@@ -13,9 +13,8 @@ WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-Taken from https://github.com/gvx/bitser,
-Removed love specific features
-
+NOTE: Taken from https://github.com/gvx/bitser @ 1d3ebe04cfd6ef2dd8ebd212a6ad06e96dfdc170,
+      Removed love specific features.
 ]]
 
 local VERSION = '1.1'
@@ -34,6 +33,7 @@ local buf = nil
 local buf_is_writable = true
 local writable_buf = nil
 local writable_buf_size = nil
+local includeMetatables = true -- togglable with bitser.includeMetatables(false)
 local SEEN_LEN = {}
 
 local function Buffer_prereserve(min_size)
@@ -202,7 +202,7 @@ local function write_table(value, seen)
 		classkey = classkey_registry[classname]
 		Buffer_write_byte(242)
 		serialize_value(classname, seen)
-	elseif metatable then
+	elseif includeMetatables and metatable then
 		Buffer_write_byte(253)
 	else
 		Buffer_write_byte(240)
@@ -225,7 +225,7 @@ local function write_table(value, seen)
 			serialize_value(v, seen)
 		end
 	end
-	if metatable and not classname then
+	if includeMetatables and metatable and not classname then
 		serialize_value(metatable, seen)
 	end
 end
@@ -327,7 +327,9 @@ local function deserialize_value(seen)
 			v[key] = deserialize_value(seen)
 		end
 		if t == 253 then
-			setmetatable(v, deserialize_value(seen))
+			if includeMetatables then
+				setmetatable(v, deserialize_value(seen))
+			end
 		end
 		return v
 	elseif t == 241 then
@@ -427,6 +429,8 @@ end, loads = function(str)
 	end
 	Buffer_newReader(str)
 	return deserialize_value({})
+end, includeMetatables = function(bool)
+	includeMetatables = not not bool
 end, register = function(name, resource)
 	assert(not resource_registry[name], name .. " already registered")
 	resource_registry[name] = resource

ffi/sha2.lua

@@ -49,6 +49,7 @@
 --     2     2018-10-07   Decreased module loading time in Lua 5.1 implementation branch (thanks to Peter Melnichenko for giving a hint)
 --     1     2018-10-06   First release (only SHA-2 functions)
 -----------------------------------------------------------------------------
+-- NOTE: This is https://github.com/Egor-Skriptunoff/pure_lua_SHA @ 304d4121f080e68ef209d3f5fe093e5a955a4978
 
 local print_debug_messages = false  -- set to true to view some messages about your system's abilities and implementation branch chosen for your system