Workaround a (Windows) linker bug when doing a PGO build.

webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.cc

Index: webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.cc
diff --git a/webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.cc b/webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.cc
index 4e665ea45525e3db61fb6ef7a3ebce74e53478e5..5536ea42640002ac6a24044ff7023b88a0728a13 100644
--- a/webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.cc
+++ b/webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.cc
@@ -272,6 +272,11 @@ int AudioCodingModuleImpl::SendFrequency() const {
 // TODO(henrik.lundin): Remove; not used.
 int AudioCodingModuleImpl::SendBitrate() const {
   FATAL() << "Deprecated";
+  // This return statement is required to workaround a bug in VS2013 Update 4
+  // when turning on the whole program optimizations. Without hit the linker
+  // will hang because it doesn't seem to find an exit path for this function.
+  // This is likely a bug in link.exe and would probably be fixed in VS2015.
+  return -1;
   //  CriticalSectionScoped lock(acm_crit_sect_);
   //
   //  if (!codec_manager_.current_encoder()) {