Modifies readline() to behave in the same way as it does in TraceMonkey.

src/d8.cc

 // Copyright 2009 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 162 matching lines @@
   }
   Handle<String> source = ReadFile(*file);
   if (source.IsEmpty()) {
     return ThrowException(String::New("Error loading file"));
   }
   return source;
 }
 
 
 Handle<Value> Shell::ReadLine(const Arguments& args) {
-  char line_buf[256];
-  if (fgets(line_buf, sizeof(line_buf), stdin) == NULL) {
-    return ThrowException(String::New("Error reading line"));
+  i::SmartPointer<char> line(i::ReadLine(""));
+  if (*line == NULL) {
+    return Null();
   }
-  int len = strlen(line_buf);
-  if (line_buf[len - 1] == '\n') {
+  size_t len = strlen(*line);
+  if (len > 0 && line[len - 1] == '\n') {
     --len;
   }
-  return String::New(line_buf, len);
+  return String::New(*line, len);
 }
 
 
 Handle<Value> Shell::Load(const Arguments& args) {
   for (int i = 0; i < args.Length(); i++) {
     HandleScope handle_scope;
     String::Utf8Value file(args[i]);
     if (*file == NULL) {
       return ThrowException(String::New("Error loading file"));
     }
@@ skipping 562 matching lines @@
   return 0;
 }
 
 
 }  // namespace v8
 
 
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }