luaL_optstring   5856 host/minilua.c #define luaL_optstring(L,n,d)(luaL_optlstring(L,(n),(d),NULL))
luaL_optstring    104 lauxlib.h      #define luaL_optstring(L,n,d)	(luaL_optlstring(L, (n), (d), NULL))