diff --git a/sys/modules/if_tun/Makefile b/sys/modules/if_tun/Makefile
index 8d97cce832af..6011be0379fa 100644
--- a/sys/modules/if_tun/Makefile
+++ b/sys/modules/if_tun/Makefile
@@ -15,7 +15,11 @@ opt_atalk.h:
 	echo "#define NETATALK 1" > opt_atalk.h
 
 opt_atm.h:
-	echo "#define ATM_CORE 1" > opt_atm.h
+	echo "#ifdef __i386__" > opt_atm.h
+	echo "#define ATM_CORE 1" >> opt_atm.h
+	echo "#else" >>opt_atm.h
+	echo "#undef ATM_CORE" >>opt_atm.h
+	echo "#endif" >>opt_atm.h
 
 opt_inet.h:
 	echo "#define INET 1" > opt_inet.h