kern.post.mk: Replace "mkdir -p" with "install -d"

to create the 'dir' entry in METALOG

Signed-off-by: Marian Cingel <cingel.marian@gmail.com>
Reviewed by: imp, kevans
Pull Request: freebsd#1967

Author: marian-cingel

sys/conf/kern.post.mk

@@ -457,7 +457,7 @@ kernel-install: .PHONY
 	${INSTALL} -p -m ${KMODMODE} -o ${KMODOWN} -g ${KMODGRP} ${KERNEL_KO}.debug ${DESTDIR}${KERN_DEBUGDIR}${KODIR}/
 	${INSTALL} -m ${KMODMODE} -o ${KMODOWN} -g ${KMODGRP} \
 	    $S/tools/kernel-gdb.py ${DESTDIR}${KERN_DEBUGDIR}${KODIR}/${KERNEL_KO}-gdb.py
-	mkdir -p ${DESTDIR}${KERN_DEBUGDIR}${KODIR}/gdb
+	${INSTALL} -d -o ${KMODOWN} -g ${KMODGRP} ${DESTDIR}${KERN_DEBUGDIR}${KODIR}/gdb
 .for file in ${GDB_FILES}
 	${INSTALL} -m ${KMODMODE} -o ${KMODOWN} -g ${KMODGRP} \
 	    $S/tools/gdb/${file} ${DESTDIR}${KERN_DEBUGDIR}${KODIR}/gdb/${file}