Move mildenhall theme from /var to /usr

The mildenhall themes are located in /var/lib/MILDENHALL_extensions.
Move this directory to /usr/share when building OSTree images.
Add a symbolic link so that unmodified binaries can still run.

Apertis: https://phabricator.apertis.org/T5362


Signed-off-by: Frédéric Dalleau <frederic.dalleau@collabora.com>

apertis-ostree-commit.yaml

@@ -53,6 +53,11 @@ actions:
     chroot: true
     script: scripts/canterbury-platform-cache.sh
 
+  - action: run
+    description: Move theme directory
+    chroot: true
+    script: scripts/mildenhall-extensions-theme.sh
+
   - action: run
     chroot: true
     script: scripts/ostree-prepare.sh

scripts/mildenhall-extensions-theme.sh

+#!/bin/sh
+
+set -e
+
+TMPFILE=/usr/lib/tmpfiles.d/mildenhall-extensions.conf
+SOURCE=/var/lib/
+TARGET=/usr/share/
+MILDENHALL=MILDENHALL_extensions
+
+# Move the MILDENHALL_extensions directory to /usr/share
+mkdir -p $TARGET
+mv $SOURCE/$MILDENHALL $TARGET/
+
+# Create a symbolic link at the standard place
+echo "L+ $SOURCE/$MILDENHALL - - - - $TARGET/$MILDENHALL" > $TMPFILE
+