Prep to remove API-related #defines from voice_engine_configurations.h

webrtc/voice_engine/voe_audio_processing_impl.cc

Index: webrtc/voice_engine/voe_audio_processing_impl.cc
diff --git a/webrtc/voice_engine/voe_audio_processing_impl.cc b/webrtc/voice_engine/voe_audio_processing_impl.cc
index afbf29ab18d8ce682bab7f4ddccf8408f1775334..d38717c4608832b5aa4c22a9f6ab885b73e57ab4 100644
--- a/webrtc/voice_engine/voe_audio_processing_impl.cc
+++ b/webrtc/voice_engine/voe_audio_processing_impl.cc
@@ -18,6 +18,10 @@
 #include "webrtc/voice_engine/transmit_mixer.h"
 #include "webrtc/voice_engine/voice_engine_impl.h"
 
+#ifndef WEBRTC_VOICE_ENGINE_AUDIO_PROCESSING_API
+#error "Deprecated"
+#endif
+
 // TODO(andrew): move to a common place.
 #define WEBRTC_VOICE_INIT_CHECK()                        \
   do {                                                   \