--- /usr/src/sys/conf/kern.post.mk	(revision 346252)
+++ /usr/src/sys/conf/kern.post.mk	(working copy)
@@ -85,7 +85,8 @@ 
 all:
 .for __i in ${PORTS_MODULES}
 	@${ECHO} "===> Ports module ${__i} (all)"
-	cd $${PORTSDIR:-/usr/ports}/${__i}; ${PORTSMODULESENV} ${MAKE} -B clean build
+	${PORTSMODULESENV} ${MAKE} -C "$${PORTSDIR:-/usr/ports}/${__i}" clean
+	${PORTSMODULESENV} ${MAKE} -C "$${PORTSDIR:-/usr/ports}/${__i}" build
 .endfor
 
 .for __target in install reinstall clean
@@ -93,7 +94,8 @@ 
 ports-${__target}:
 .for __i in ${PORTS_MODULES}
 	@${ECHO} "===> Ports module ${__i} (${__target})"
-	cd $${PORTSDIR:-/usr/ports}/${__i}; ${PORTSMODULESENV} ${MAKE} -B ${__target:C/(re)?install/deinstall reinstall/}
+	${PORTSMODULESENV} ${MAKE} -C "$${PORTSDIR:-/usr/ports}/${__i}" \
+	    ${__target:C/(re)?install/deinstall reinstall/}
 .endfor
 .endfor
 .endif