Index: head/Mk/bsd.port.mk
===================================================================
--- head/Mk/bsd.port.mk
+++ head/Mk/bsd.port.mk
@@ -605,7 +605,7 @@
 #				  for this port.
 # install-missing-packages
 #               - Install missing dependencies from package and mark
-#                 them as automatically installed 
+#                 them as automatically installed.
 # extract		- Unpacks ${DISTFILES} into ${WRKDIR}.
 # patch			- Apply any provided patches to the source.
 # configure		- Runs either GNU configure, one or more local configure
@@ -4332,7 +4332,8 @@
 # Install missing dependencies from package
 install-missing-packages:
 	@_dirs=$$(${MISSING-DEPENDS-LIST}); \
-	${PKG_BIN} install -A $$(${ECHO} $${_dirs} | ${SED} "s%${PORTSDIR}/%%g")
+	[ -z "$${_dirs}" ] || \
+	${SU_CMD} "${PKG_BIN} install -A $$(${ECHO} $${_dirs} | ${SED} "s%${PORTSDIR}/%%g")"
 
 ################################################################
 # Everything after here are internal targets and really