long strings are created directly in final position when possible

(instead of using an auxiliar buffer to first create the string
and then allocate the final string and copy result there)

lzio.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lzio.h,v 1.29 2014/12/19 13:45:40 roberto Exp roberto $
+** $Id: lzio.h,v 1.30 2014/12/19 17:26:14 roberto Exp roberto $
 ** Buffered streams
 ** See Copyright Notice in lua.h
 */
@@ -44,7 +44,6 @@ typedef struct Mbuffer {
 #define luaZ_freebuffer(L, buff)	luaZ_resizebuffer(L, buff, 0)
 
 
-LUAI_FUNC char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n);
 LUAI_FUNC void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader,
                                         void *data);
 LUAI_FUNC size_t luaZ_read (ZIO* z, void *b, size_t n);	/* read next n bytes */