release: Pass PKG_INSTALL_EPOCH to vmimage.subr

This value, if not already set, comes from the timestamp of the most
recent git commit (which is now also available in src/release code as
GITEPOCH) or 0 if git is not installed.

This should allow /var/db/pkg/local.sqlite to be reproducible in VM
images which have packages installed (e.g. cloudware).

Reviewed by:	emaste, bapt
MFC after:	5 days
Sponsored by:	Amazon
Differential Revision:	https://reviews.freebsd.org/D49760

release/Makefile.inc1

@@ -1,6 +1,3 @@
-#
-#
-
 # Figure out where the git binary is.
 .for _P in /usr/bin /usr/local/bin
 . if !defined(GIT_CMD) || empty(GIT_CMD)
@@ -24,13 +21,19 @@ GITREV!=	${GIT_CMD} -C ${.CURDIR} rev-parse --verify --short HEAD 2>/dev/null ||
 GITCOUNT!=	${GIT_CMD} -C ${.CURDIR} rev-list --first-parent --count HEAD 2>/dev/null || true
 . export GITCOUNT
 . endif
+. if !defined(GITEPOCH) || empty(GITEPOCH)
+GITEPOCH!=	${GIT_CMD} -C ${.CURDIR} show -s --format=%ct HEAD 2>/dev/null || true
+. export GITEPOCH
+. endif
 .else
 GITBRANCH=	nullbranch
 GITREV=		nullhash
 GITCOUNT=	nullcount
+GITEPOCH=	0
 . export GITBRANCH
 . export GITREV
 . export GITCOUNT
+. export GITEPOCH
 .endif
 
 # Set the build date, primarily for snapshot builds.

release/Makefile.vm

@@ -181,6 +181,7 @@ vm-image:	${QEMUTGT}
 		QEMUSTATIC=${QEMUSTATIC} \
 		${WITHOUT_QEMU:DWITHOUT_QEMU=true} \
 		${NO_ROOT:DNO_ROOT=true} \
+		PKG_INSTALL_EPOCH=${PKG_INSTALL_EPOCH:U${GITEPOCH}} \
 		${.CURDIR}/scripts/mk-vmimage.sh \
 		-C ${.CURDIR}/tools/vmimage.subr \
 		-d ${.OBJDIR}/${.TARGET}-${FORMAT}-${FS} -F ${FS} \