[gnome-builder] flatpak: allow to use and create meson cross-compilation files

[Corentin Noël <corentinnoel src gnome org>]

commit 173f0fc0bc81ce8b5be3bef70e62dffaaac07d74
Author: Corentin Noël <corentin noel collabora com>
Date:   Tue Jun 26 17:45:52 2018 +0100

    flatpak: allow to use and create meson cross-compilation files

 build-aux/flatpak/org.gnome.Builder.json | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/build-aux/flatpak/org.gnome.Builder.json b/build-aux/flatpak/org.gnome.Builder.json
index 7647f7394..8a00ed13a 100644
--- a/build-aux/flatpak/org.gnome.Builder.json
+++ b/build-aux/flatpak/org.gnome.Builder.json
@@ -37,6 +37,7 @@
         "--filesystem=/etc/pki:ro",
         "--filesystem=/etc/ca-certificates:ro",
         "--filesystem=~/.local/share/flatpak",
+        "--filesystem=~/.local/share/meson",
         "--filesystem=/var/lib/flatpak"
     ],
     "x-run-args" : [