stand allow for local.defs.mk

This allows us to change the VERSION_FILE used for loaders
as well as set NEWVERS_DATE and BUILD_UTC to reflect the publish
date of loaders for secure-boot.

Sponsored by:	Juniper Networks, Inc.

Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D50478

stand/common/newvers.sh

@@ -50,13 +50,17 @@ if [ -n "$SOURCE_DATE_EPOCH" ]; then
 		exit 1
 	fi
 else
-	t=`date`
+	t="${NEWVERS_DATE:-`date`}"
 fi
 r=`awk -F: ' /^[0-9]\.[0-9]+:/ { print $1; exit }' $1`
 
 bootprog_info="FreeBSD/${3} ${2}, Revision ${r}\\n"
 if [ -n "${include_metadata}" ]; then
 	bootprog_info="$bootprog_info(${t} ${u}@${h})\\n"
+	if [ -n "$BUILD_UTC" ]; then
+		# We can use what(1) to extract BUILD_UTC
+		bootprog_info="$bootprog_info\\0@(#)BUILD_UTC=$BUILD_UTC"
+	fi
 fi
 
 cat > $tempfile <<EOF

stand/defs.mk

@@ -258,4 +258,6 @@ ${_ILINKS}: .NOMETA
 	${ECHO} ${.TARGET} "->" $$path ; \
 	ln -fns $$path ${.TARGET}
 .endif # !NO_OBJ
+
+.-include "local.defs.mk"
 .endif # __BOOT_DEFS_MK__

stand/efi/loader/Makefile

@@ -87,7 +87,7 @@ CFLAGS+= -DEFI_SECUREBOOT
 .endif
 
 NEWVERSWHAT?=	"EFI loader" ${MACHINE}
-VERSION_FILE=	${.CURDIR}/../loader/version
+VERSION_FILE?=	${.CURDIR}/../loader/version
 HELP_FILENAME=	loader.help.efi
 
 # Always add MI sources

stand/i386/loader/Makefile

@@ -16,7 +16,7 @@ LOADER?=	loader_${LOADER_INTERP}
 PROG=		${LOADER}.sym
 INTERNALPROG=
 NEWVERSWHAT?=	"bootstrap loader" x86
-VERSION_FILE=	${.CURDIR}/../loader/version
+VERSION_FILE?=	${.CURDIR}/../loader/version
 #
 # There's 640k - 40k maximum space, less however much memory the BIOS uses.  A
 # non-random survey suggests that 20k-25k is a good value for 'most' machines.