[gnome-builder] plugins/meson-templates: wire up vala sdk extension

[Christian Hergert <chergert src gnome org>]

commit bfa3c01ff590a8821c83bd09d1b66eeeeb4f8776
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jul 15 22:29:43 2022 -0700

    plugins/meson-templates: wire up vala sdk extension

 src/plugins/meson-templates/resources/flatpak.json.in | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/src/plugins/meson-templates/resources/flatpak.json.in 
b/src/plugins/meson-templates/resources/flatpak.json.in
index 6112dabcd..2482956b9 100644
--- a/src/plugins/meson-templates/resources/flatpak.json.in
+++ b/src/plugins/meson-templates/resources/flatpak.json.in
@@ -7,6 +7,10 @@
     "sdk-extensions" : [
         "org.freedesktop.Sdk.Extension.rust-stable"
     ],
+{{else if language == "vala"}}
+    "sdk-extensions" : [
+        "org.freedesktop.Sdk.Extension.vala"
+    ],
 {{end}}
     "command" : "{{exec_name}}",
     "finish-args" : [
@@ -29,6 +33,11 @@
             "RUST_LOG" : "{{name}}=debug"
         }
     },
+{{else if language == "vala"}}
+    "build-options" : {
+        "append-path" : "/usr/lib/sdk/vala/bin",
+        "prepend-ld-library-path" : "/usr/lib/sdk/vala/lib"
+    },
 {{end}}
     "cleanup" : [
         "/include",