ww: implement package initialization

lib/bufio/stream.ww

@@ -75,7 +75,7 @@ export type stream = struct {
 //
 // Returns the stream BY VALUE; the caller passes `&b.vt` to the io
 // dispatchers. Mirrors ref/hare/bufio/stream.ha:69.
-export fn init(src: io.stream, rbuf: []u8, wbuf: []u8) stream = {
+export fn newstream(src: io.stream, rbuf: []u8, wbuf: []u8) stream = {
 	let r: stream;
 	r.vt.reader = (&bread):  *io.reader;
 	r.vt.writer = (&bwrite): *io.writer;