Index: Mk/bsd.port.mk
===================================================================
--- Mk/bsd.port.mk
+++ Mk/bsd.port.mk
@@ -1361,7 +1361,7 @@
 .include "${PORTSDIR}/Mk/bsd.local.mk"
 .endif
 
-.if defined(USE_XORG) && (!defined(USES) || !${USES:Mxorg})
+.if !empty(USE_XORG) && (!defined(USES) || !${USES:Mxorg})
 DEV_WARNING+=		"Using USE_XORG alone is deprecated, please use USES=xorg"
 USES+=	xorg
 .endif
@@ -1943,7 +1943,7 @@
 .include "${PORTSDIR}/Mk/bsd.local.mk"
 .endif
 
-.if defined(USE_XORG) && (!defined(USES) || ( defined(USES) && !${USES:Mxorg} ))
+.if !empty(USE_XORG) && (!defined(USES) || ( defined(USES) && !${USES:Mxorg} ))
 DEV_WARNING+=	"Using USE_XORG alone is deprecated, please use USES=xorg"
 _USES_POST+=	xorg
 .endif