diff -upr fpc-2.6.2.org/packages/lua/src/lauxlib.pas fpc-2.6.2.mod/packages/lua/src/lauxlib.pas
--- fpc-2.6.2.org/packages/lua/src/lauxlib.pas	2009-08-31 17:55:09.000000000 +0900
+++ fpc-2.6.2.mod/packages/lua/src/lauxlib.pas	2013-10-19 20:52:36.000000000 +0900
@@ -289,7 +289,7 @@ end;
 
 procedure luaL_addchar(B: PluaL_Buffer; c: Char);
 begin
-  if Cardinal(@(B^.p)) < (Cardinal(@(B^.buffer[0])) + LUAL_BUFFERSIZE) then
+  if qword(@(B^.p)) < (qword(@(B^.buffer[0])) + LUAL_BUFFERSIZE) then
     luaL_prepbuffer(B);
   B^.p[1] := c;
   B^.p := B^.p + 1;
diff -upr fpc-2.6.2.org/packages/lua/src/lua.pas fpc-2.6.2.mod/packages/lua/src/lua.pas
--- fpc-2.6.2.org/packages/lua/src/lua.pas	2012-01-09 17:27:40.000000000 +0900
+++ fpc-2.6.2.mod/packages/lua/src/lua.pas	2013-10-19 20:38:06.000000000 +0900
@@ -52,7 +52,11 @@ const
 {$ENDIF}
 
 type
-  size_t = Cardinal;
+{$IFDEF CPU64}
+  size_t   = qword;
+{$ELSE CPU64}
+  size_t   = longword;
+{$ENDIF CPU64}
   Psize_t = ^size_t;
 
 const