update engine: 32- and 64-bit compile

src/platform/update_engine/gzip.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "update_engine/gzip.h"
 #include <stdlib.h>
 #include <algorithm>
 #include <zlib.h>
 #include "chromeos/obsolete_logging.h"
 #include "update_engine/utils.h"
@@ skipping 75 matching lines @@
   z_stream stream;
   memset(&stream, 0, sizeof(stream));
   TEST_AND_RETURN_FALSE(deflateInit2(&stream,
                                       Z_BEST_COMPRESSION,
                                       Z_DEFLATED,
                                       16 + MAX_WBITS,
                                       9,  // most memory used/best compression
                                       Z_DEFAULT_STRATEGY) == Z_OK);
 
   // guess that output will be roughly half the input size
-  *out_size = max(1U, in_size / 2);
+  *out_size = max(static_cast<size_t>(1), in_size / 2);
   *out = reinterpret_cast<char*>(malloc(*out_size));
   TEST_AND_RETURN_FALSE(*out);
 
   // TODO(adlr): ensure that this const_cast is safe.
   stream.next_in = const_cast<Bytef*>(reinterpret_cast<const Bytef*>(in));
   stream.avail_in = in_size;
   stream.next_out = reinterpret_cast<Bytef*>(*out);
   stream.avail_out = *out_size;
   for (;;) {
     int rc = deflate(&stream, Z_FINISH);
@@ skipping 69 matching lines @@
   char* out_buf;
   size_t out_size;
   TEST_AND_RETURN_FALSE(GzipDecompressData(str.data(), str.size(),
                                             &out_buf, &out_size));
   out->insert(out->end(), out_buf, out_buf + out_size);
   free(out_buf);
   return true;
 }
 
 } // namespace chromeos_update_engine