This fixes a number of things that are warnings in the Mac compiler....

core/cross/buffer.cc

 /*
  * Copyright 2009, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 82 matching lines @@
   { UByteNField::GetApparentClass(), UByteNField::Create,
     UByteNField::kRequiredComponentMultiple, },
 };
 
 }  // anonymouse namespace.
 
 // Buffer ---------------
 Buffer::Buffer(ServiceLocator* service_locator)
     : NamedObject(service_locator),
       features_(service_locator->GetService<Features>()),
-      access_mode_(NONE),
       field_change_count_(0),
       total_components_(0),
       stride_(0),
       num_elements_(0),
+      access_mode_(NONE),
       lock_count_(0) {
 }
 
 Buffer::~Buffer() {
   AdjustBufferMemoryInfo(false);
   for (unsigned ii = 0; ii < fields_.size(); ++ii) {
     if (!fields_[ii].IsNull()) {
       fields_[ii]->ClearBuffer();
     }
   }
@@ skipping 349 matching lines @@
   int32 num_elements = stream.ReadLittleEndianInt32();
   if (!AllocateElements(num_elements)) {
     O3D_ERROR(service_locator()) << "could not allocate buffer elements";
     return false;
   }
 
   {
     // Lock before reading in all the fields to avoid locking/unlocking
     // for each field which would be slower
     o3d::BufferLockHelper helper(this);
-    void *buffer_data = helper.GetData(o3d::Buffer::WRITE_ONLY);
+    helper.GetData(o3d::Buffer::WRITE_ONLY);
 
     // Read each field
     for (int32 ff = 0; ff < num_fields; ++ff) {
       Field *field = fields()[ff];
       if (!field->SetFromMemoryStream(&stream)) {
         O3D_ERROR(service_locator()) <<
             "unexpected end of buffer field data";
         return false;
       }
     }
@@ skipping 109 matching lines @@
     locked_ = buffer_->Lock(access_mode, &data_);
     if (!locked_) {
       O3D_ERROR(buffer_->service_locator())
           << "Unable to lock buffer '" << buffer_->name() << "'";
     }
   }
   return data_;
 }
 
 }  // namespace o3d