Index: config/version.sh
===================================================================
--- a/config/version.sh
+++ b/config/version.sh
@@ -11,9 +11,9 @@
     git=" `git -C $srcdir describe --long --dirty`"
 else
     git=
 fi
-date="`TZ=GMT0 date +'%Y-%m-%d %T'` +0000"
+date="$(date --utc --date="@${SOURCE_DATE_EPOCH:-$(date +%s)}" +%Y-%m-%d)"
 
 cat <<E
 char *version_str = "nmh-$version$git built $date on $host";
 char *version_num = "nmh-$version";