add default card for macosx

diff --git a/mediastreamer2 b/mediastreamer2
index 66ca17758ae34aad009f6f737ffd1fb744525818..39a3f4ddd4a0f60cdd563fdef1d1b7d6e04d140d 160000 (submodule)
--- a/mediastreamer2
+++ b/mediastreamer2
@@ -1 +1 @@
-Subproject commit 66ca17758ae34aad009f6f737ffd1fb744525818
+Subproject commit 39a3f4ddd4a0f60cdd563fdef1d1b7d6e04d140d