luaM_reallocv
newblock = luaM_reallocv(L, block, *size, newsize, size_elems);
#define luaM_freearray(L, b, n) luaM_reallocv(L, (b), n, 0, sizeof((b)[0]))
cast(t *, luaM_reallocv(L, NULL, 0, n, sizeof(t)))
((v)=cast(t *, luaM_reallocv(L, v, oldn, n, sizeof(t))))