cmake(rtcpdemux): process warnings as errors
cmake(rtcpdemux): process warnings as errors

Change-Id: I148ccd84c214bbe8bb7ec2993bd53e1f8b1eacfb

Kurento/kms-elements,shelsonjava/kms-elements,TribeMedia/kms-elements,shelsonjava/kms-elements,shelsonjava/kms-elements,TribeMedia/kms-elements,Kurento/kms-elements,Kurento/kms-elements,TribeMedia/kms-elements