Searching the alsa-project.org website for ipc_key_add_uid indicates that this feature was removed before v 1.0.10 ?
<http://www.alsa-project.org/main/index.php/Changes_1.0.9_v1.0.10>
+ Configuration
- Summary: use ipc_gid for dmix and dsnoop
- added ipc_gid audio
- removed ipc_key_add_uid