Fix warnings on Win64.

src/flags.cc

 // Copyright 2006-2008 the V8 project authors. 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.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 285 matching lines @@
     }
     *name = arg;
 
     // find the end of the flag name
     while (*arg != '\0' && *arg != '=')
       arg++;
 
     // get the value if any
     if (*arg == '=') {
       // make a copy so we can NUL-terminate flag name
-      int n = arg - *name;
-      CHECK(n < buffer_size);  // buffer is too small
+      size_t n = arg - *name;
+      CHECK(n < static_cast<size_t>(buffer_size));  // buffer is too small
       memcpy(buffer, *name, n);
       buffer[n] = '\0';
       *name = buffer;
       // get the value
       *value = arg + 1;
     }
   }
 }
 
 
@@ skipping 228 matching lines @@
 const char** JSArguments::argv() { return argv_; }
 const char*& JSArguments::operator[](int idx) { return argv_[idx]; }
 JSArguments& JSArguments::operator=(JSArguments args) {
     argc_ = args.argc_;
     argv_ = args.argv_;
     return *this;
 }
 
 
 } }  // namespace v8::internal