release: Prepare GCE cloudware images for building as non-root

- Avoid mounting devfs just to list packages and fetch distfiles.
- Add metalog entries.

Reviewed by:	cperciva, emaste
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D52455

release/tools/gce.conf

@@ -21,6 +21,7 @@ vm_extra_install_base() {
 	echo 'search google.internal' > ${DESTDIR}/etc/resolv.conf
 	echo 'nameserver 169.254.169.254' >> ${DESTDIR}/etc/resolv.conf
 	echo 'nameserver 8.8.8.8' >> ${DESTDIR}/etc/resolv.conf
+	metalog_add ./etc/resolv.conf
 }
 
 vm_extra_pre_umount() {
@@ -94,25 +95,18 @@ EOF
 	# ports.txz distributions to the target virtual machine disk image
 	# and fetch the sources for the third-party software installed on
 	# the image.
-	if [ ! -c "${DESTDIR}/dev/null" ]; then
-		DEVFSISOURS=1
-		mkdir -p ${DESTDIR}/dev
-		mount -t devfs devfs ${DESTDIR}/dev
-	fi
 	if [ -e "${DESTDIR}/../ftp/src.txz" ]; then
 		tar fxJ ${DESTDIR}/../ftp/src.txz -C ${DESTDIR}
 	fi
 	if [ -e "${DESTDIR}/../ftp/ports.txz" ]; then
 		tar fxJ ${DESTDIR}/../ftp/ports.txz -C ${DESTDIR}
-		_INSTALLED_PACKAGES=$(chroot ${DESTDIR} pkg info -o -q -a)
+		_INSTALLED_PACKAGES=$(pkg -r ${DESTDIR} info -o -q -a)
 		for PACKAGE in ${_INSTALLED_PACKAGES}; do
-			chroot ${DESTDIR} \
-				make -C /usr/ports/${PACKAGE} fetch
+			make -C ${DESTDIR}/usr/ports/${PACKAGE} fetch \
+			    DISTDIR=${DESTDIR}/usr/ports/distfiles
+
 		done
 	fi
-	if [ "$DEVFSISOURS" = "1" ]; then
-		umount_loop ${DESTDIR}/dev
-	fi
 
 	## XXX: Verify this is needed.  I do not see this requirement
 	## in the docs, and it impairs the ability to boot-test a copy
@@ -128,6 +122,5 @@ vm_emulation_cleanup() {
 	if [ -n "${QEMUSTATIC}" ]; then
 		rm -f ${DESTDIR}/${EMULATOR}
 	fi
-	umount_loop ${DESTDIR}/dev
 	return 0
 }