strdup is done via mem.c to control its memory allocation

luamem.h

@@ -1,7 +1,7 @@
 /*
 ** mem.c
 ** memory manager for lua
-** $Id: $
+** $Id: mem.h,v 1.1 1994/11/16 17:38:08 roberto Stab roberto $
 */
  
 #ifndef mem_h
@@ -15,6 +15,8 @@ void luaI_free (void *block);
 void *luaI_malloc (unsigned long size);
 void *luaI_realloc (void *oldblock, unsigned long size);
 
+char *luaI_strdup (char *str);
+
 #define new(s)          ((s *)luaI_malloc(sizeof(s)))
 #define newvector(n,s)  ((s *)luaI_malloc((n)*sizeof(s)))
 #define growvector(old,n,s) ((s *)luaI_realloc(old,(n)*sizeof(s)))