cutils: return the remote uid on netlink recv failure

This change adds a layer of indirection to uevent's
uevent_kernel_multicast_recv, allowing dependent code to
get the remote endpoint if desired.

Change-Id: If2f00708a1dd6196c415b1ebc2a7eeb72399a90e
diff --git a/include/cutils/uevent.h b/include/cutils/uevent.h
index 4ebc300..4cca7e5 100644
--- a/include/cutils/uevent.h
+++ b/include/cutils/uevent.h
@@ -26,6 +26,7 @@
 
 int uevent_open_socket(int buf_sz, bool passcred);
 ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length);
+ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer, size_t length, uid_t *uid);
 
 #ifdef __cplusplus
 }