diff --git a/sys/dev/ath/ath_hal/ah_desc.h b/sys/dev/ath/ath_hal/ah_desc.h
index 2ef7b85f4c08..b7d4e2daee73 100644
--- a/sys/dev/ath/ath_hal/ah_desc.h
+++ b/sys/dev/ath/ath_hal/ah_desc.h
@@ -22,6 +22,17 @@
 
 #include "opt_ah.h"		/* NB: required for AH_SUPPORT_AR5416 */
 
+/*
+ * For now, define this for the structure definitions.
+ * Because of how the HAL / driver module currently builds,
+ * it's not very feasible to build the module without
+ * this defined.  The rest of the code (eg in the driver
+ * body) can work fine with these fields being uninitialised;
+ * they'll be initialised to 0 anyway.
+ */
+
+#define	AH_SUPPORT_AR5416	1
+
 /*
  * Transmit descriptor status.  This structure is filled
  * in only after the tx descriptor process method finds a