Handshaker plugin mechanism.
diff --git a/config.m4 b/config.m4
index 4b86e25..12b1057 100644
--- a/config.m4
+++ b/config.m4
@@ -88,6 +88,8 @@
     src/core/lib/channel/connected_channel.c \
     src/core/lib/channel/deadline_filter.c \
     src/core/lib/channel/handshaker.c \
+    src/core/lib/channel/handshaker_factory.c \
+    src/core/lib/channel/handshaker_registry.c \
     src/core/lib/channel/http_client_filter.c \
     src/core/lib/channel/http_server_filter.c \
     src/core/lib/channel/message_size_filter.c \