Revert "third_party/protobuf: Update to HEAD (83d681ee2c)"

third_party/protobuf/objectivec/GPBUnknownField.m

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // 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 49 matching lines @@
 - (void)dealloc {
   [mutableVarintList_ release];
   [mutableFixed32List_ release];
   [mutableFixed64List_ release];
   [mutableLengthDelimitedList_ release];
   [mutableGroupList_ release];
 
   [super dealloc];
 }
 
-// Direct access is use for speed, to avoid even internally declaring things
-// read/write, etc. The warning is enabled in the project to ensure code calling
-// protos can turn on -Wdirect-ivar-access without issues.
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wdirect-ivar-access"
-
 - (id)copyWithZone:(NSZone *)zone {
   GPBUnknownField *result =
       [[GPBUnknownField allocWithZone:zone] initWithNumber:number_];
   result->mutableFixed32List_ = [mutableFixed32List_ copyWithZone:zone];
   result->mutableFixed64List_ = [mutableFixed64List_ copyWithZone:zone];
   result->mutableLengthDelimitedList_ =
       [mutableLengthDelimitedList_ copyWithZone:zone];
   result->mutableVarintList_ = [mutableVarintList_ copyWithZone:zone];
   if (mutableGroupList_.count) {
     result->mutableGroupList_ = [[NSMutableArray allocWithZone:zone]
@@ skipping 236 matching lines @@
 }
 
 - (void)addGroup:(GPBUnknownFieldSet *)value {
   if (mutableGroupList_ == nil) {
     mutableGroupList_ = [[NSMutableArray alloc] initWithObjects:&value count:1];
   } else {
     [mutableGroupList_ addObject:value];
   }
 }
 
-#pragma clang diagnostic pop
-
 @end