make ice_socket public

Change-Id: Ib2abfd7d6dc0d2647549e633e6b8ea7d4ba65060
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7086126..47740a5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -44,6 +44,7 @@
     include/certstore.h
     include/ice_options.h
     include/ice_transport.h
+    include/ice_socket.h
     include/fileutils.h
     include/string_utils.h
     include/ip_utils.h