diff --git a/Kbuild b/Kbuild
index f113518..137b91c 100644
--- a/Kbuild
+++ b/Kbuild
@@ -2808,6 +2808,8 @@
 
 cppflags-$(CONFIG_SLUB_DEBUG_ON) += -DHIF_CONFIG_SLUB_DEBUG_ON
 
+ccflags-$(CONFIG_FOURTH_CONNECTION) += -DFEATURE_FOURTH_CONNECTION
+
 KBUILD_CPPFLAGS += $(cppflags-y)
 
 # Currently, for versions of gcc which support it, the kernel Makefile