build: fix clang compilation

missing header <functional>, change introduced in 989e9bdb Issue: #78983 Change-Id: I0f8e3a57d13d85e982a9fcd8a38e57b9f19afc8a

build: fix clang compilation
461a906b · Alexandre Lision · 87624f98 · 461a906b
Commit 461a906b authored Sep 1, 2015 by Alexandre Lision
--- a/src/ice_socket.h
+++ b/src/ice_socket.h
@@ -30,6 +30,7 @@
 #define ICE_SOCKET_H
 #include <memory>
+#include <functional>
 namespace ring {