Be compatible with LaTeX-dev main branch

luametalatex-init.lua

@@ -67,9 +67,11 @@ do
     return kpse.find_file(name, 'tex', true)
   end
   if status.ini_version then
+    function unhook_expl()
+      callback_register('find_data_file', normal_find_data_file)
+    end
     callback_register('find_data_file', function(name)
       if name == 'ltexpl.ltx' then
-        callback_register('find_data_file', normal_find_data_file)
         name = 'luametalatex-ltexpl-hook'
       end
       return normal_find_data_file(name)

luametalatex-ltexpl-hook.tex

@@ -1,3 +1,6 @@
+\directlua{unhook_expl()}
 \input luametalatex-baseregisters
-\def\@tfor#1\do#2{}
+\ifx\@tfor\undefined
+  \def\@tfor#1\do#2{}
+\fi
 \input ltexpl.ltx

luametaplain.ini

@@ -13,6 +13,7 @@
 \catcode`\}=2
 \global\chardef\eTeXversion=2
 \global\def\eTeXrevision{.2}
+\directlua{unhook_expl()}
 \endgroup
 \input load-unicode-data.tex
 \input etex.src