Try to remove KIO dependency
KWin currently has an unfortunate dependency tree. That can be problematic in embedded deployments.
Most of this comes from an (indirect) dependency on KIO. KIO is required by KNewStuff, KCMUtils, and KDeclarative.
KNewStuff and KCMUtils are only needed for the KCMs, which can be not built in an embedded deployment.
The KDeclarative dep is more tricky. KF6 may fix this by removing the KIO dep in KDeclarative. For the time being it may be worth investigating whether the KDeclarative dep can be removed