Use UCL for pkg-message

Remain backward compatible but use ucl for the pkg-messages, which allows to:
- append messages one after the other
- only print message on delete, install, upgrade from a version to another

If pkg-message starts with a [ we consider it should be a valid ucl file

The format is the following:
[
{ message: "Always print" },
{ message: "package being removed", type: remove },
{ message: "package being installed", type: install },
{ message: "package is being upgraded", type: upgrade },
{ message: "Upgrading from lower than 1.0", maximum_version: "1.0", type: upgrade },
{ message: "Upgrading from higher than 1.0", minimum_version: "1.0", type: upgrade  },
{ message: "Upgrading from >1.0 < 3.0", maximum_version: "3.0", minimum_version: "1.0",
]

Because it is ucl one can use some sugar like:
[
{ message = <<EOD
formatted
message 'with fancy things'
EOD
},
}

Submitted by:	bapt
Reviewed by:	bapt, mat
Differential Revision:	https://reviews.freebsd.org/D19310

1 files changed, 17 insertions, 7 deletions

diff --git a/Mk/Scripts/create-manifest.sh b/Mk/Scripts/create-manifest.sh
index 974198cf7928..9646045987af 100644
--- a/Mk/Scripts/create-manifest.sh
+++ b/Mk/Scripts/create-manifest.sh
@@ -112,14 +112,24 @@ done
 
 exec >${dp_METADIR}/+DISPLAY
 
+echo '['
 for message in ${dp_PKGMESSAGES}; do
-  [ -f "${message}" ] && cat "${message}"
+	if [ -f "${message}" ]; then
+		#if if starts with [ then it is ucl and we do drop last and first line
+		if head -1 "${message}" | grep -q '^\['; then
+			sed '1d;$d' "${message}"
+		else
+			echo '{message=<<EOD'
+			cat "${message}"
+			printf 'EOD\n},\n'
+		fi
+	fi
 done
 
 # Try and keep these messages in sync with check-deprecated
 if [ ${dp_MAINTAINER} = "ports@FreeBSD.org" ]; then
-	if [ -f "${dp_METADIR}/+DISPLAY" ]; then echo; fi
 	cat <<-EOT
+	{ message=<<EOD
 	===>   NOTICE:
 
 	The ${dp_PKGBASE} port currently does not have a maintainer. As a result, it is
@@ -131,12 +141,14 @@ if [ ${dp_MAINTAINER} = "ports@FreeBSD.org" ]; then
 	More information about port maintainership is available at:
 
 	https://www.freebsd.org/doc/en/articles/contributing/ports-contributing.html#maintain-port
+	EOD
+	},
 	EOT
 fi
 
 if [ -n "${dp_DEPRECATED}" ]; then
-	if [ -f "${dp_METADIR}/+DISPLAY" ]; then echo; fi
 	cat <<-EOT
+	{ message=<<EOD
 	===>   NOTICE:
 
 	This port is deprecated; you may wish to reconsider installing it:
@@ -151,8 +163,6 @@ if [ -n "${dp_DEPRECATED}" ]; then
 
 		EOT
 	fi
+	printf 'EOD\n},\n'
 fi
-
-if [ ! -s ${dp_METADIR}/+DISPLAY ]; then
-	rm -f ${dp_METADIR}/+DISPLAY
-fi
+echo ']'