io: path: update to_string() to use new b_stream interface

io/sys/darwin/path.c

@@ -1,6 +1,5 @@
 #include "posix.h"
 
-#include <blue/core/stringstream.h>
 #include <blue/ds/string.h>
 #include <blue/io/file.h>
 #include <blue/io/path.h>
@@ -376,7 +375,7 @@ void path_fini(b_object *obj, void *priv)
 	b_string_unref(path->p_pathstr);
 }
 
-void path_to_string(const b_object *obj, struct b_stream *out)
+void path_to_string(const b_object *obj, b_stream *out)
 {
 	struct b_path_p *path = b_object_get_private(obj, B_TYPE_PATH);