diff --git a/Kbuild b/Kbuild
index e8ebf4c..2b8bfed 100644
--- a/Kbuild
+++ b/Kbuild
@@ -628,6 +628,10 @@
 CDEFINES += -DWLAN_OPEN_SOURCE
 endif
 
+ifeq ($(findstring opensource, $(WLAN_ROOT)), opensource)
+CDEFINES += -DWLAN_OPEN_SOURCE
+endif
+
 KBUILD_CPPFLAGS += $(CDEFINES)
 
 # Module information used by KBuild framework