Thanks for helping out. By build.cs I suppose you are talking about the game/project Build.cs? I have tryed to include it there with no success.
I haven’t done any edits in the Wwise module other than what you proposed with the string DXSDK_DIR so I wonder why the module suddenly fails to compile. I have the Wwise module installed as a project module but I am now trying to install it as an engine plugin instead to see if that helps.