Unbork Windows 64 bit build and guard against overlong UTF-8

src/api.cc

 // Copyright 2012 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 3703 matching lines @@
         const uint16_t* data = i::ExternalTwoByteString::cast(string)->
           ExternalTwoByteStringGetData(0);
         char* current = buffer;
         for (int i = start; i < end; i++) {
           uint16_t character = data[i];
           current +=
               unibrow::Utf8::Encode(current, character, previous_character);
           previous_character = character;
         }
         *last_character = previous_character;
-        return utf8_bytes + current - buffer;
+        return static_cast<int>(utf8_bytes + current - buffer);
       }
       case i::kSeqStringTag: {
         const uint16_t* data =
             i::SeqTwoByteString::cast(string)->SeqTwoByteStringGetData(0);
         char* current = buffer;
         for (int i = start; i < end; i++) {
           uint16_t character = data[i];
           current +=
               unibrow::Utf8::Encode(current, character, previous_character);
           previous_character = character;
         }
         *last_character = previous_character;
-        return utf8_bytes + current - buffer;
+        return static_cast<int>(utf8_bytes + current - buffer);
       }
       case i::kSlicedStringTag: {
         i::SlicedString* slice = i::SlicedString::cast(string);
         unsigned offset = slice->offset();
         string = slice->parent();
         start += offset;
         end += offset;
         continue;
       }
       case i::kConsStringTag: {
@@ skipping 63 matching lines @@
     }
     i::String::WriteToFlat(*str, buffer, 0, len);
     if (nchars_ref != NULL) *nchars_ref = len;
     if (!(options & NO_NULL_TERMINATION) && capacity > len) {
       buffer[len] = '\0';
       return len + 1;
     }
     return len;
   }
 
-  if (capacity == -1 || capacity >= string_length * 3) {
+  if (capacity == -1 || capacity / 3 >= string_length) {
     int32_t previous = unibrow::Utf16::kNoPreviousCharacter;
     const int kMaxRecursion = 100;
     int utf8_bytes =
         RecursivelySerializeToUtf8(*str,
                                    buffer,
                                    0,
                                    string_length,
                                    kMaxRecursion,
                                    previous,
                                    &previous);
@@ skipping 2524 matching lines @@
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
   HandleScopeImplementer* scope_implementer =
       reinterpret_cast<HandleScopeImplementer*>(storage);
   scope_implementer->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }
 
 } }  // namespace v8::internal