diff -up luaposix-release-v34.1.1/ext/include/_helpers.c.54 luaposix-release-v34.1.1/ext/include/_helpers.c
--- luaposix-release-v34.1.1/ext/include/_helpers.c.54	2020-07-03 11:48:23.799667686 -0600
+++ luaposix-release-v34.1.1/ext/include/_helpers.c	2020-07-03 11:49:11.907158779 -0600
@@ -67,7 +67,7 @@
 #  endif
 #endif
 
-#if LUA_VERSION_NUM == 502 || LUA_VERSION_NUM == 503
+#if LUA_VERSION_NUM == 502 || LUA_VERSION_NUM == 503 || LUA_VERSION_NUM == 504
 #  define lua_objlen lua_rawlen
 #  define lua_strlen lua_rawlen
 #endif