Update list of all audio files.

This adds a script that can generate the list from the other
makefiles.

This also regenerates the list.

Bug: 6336895
Change-Id: If1546c4a3f5b1f0d7c3ca79d29383e9843b2a89d
Don't include flags in configuration change if their value hasn't changed.

This makes the check in updateFrom() match the logic in diff().

Change-Id: I3ab4e8460f7fbf985ef55b9514a8aa90d401d486