Fix GCC 4.7 warnings, which are related to char being signed in GCC

test/cctest/test-regexp.cc

 // Copyright 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 818 matching lines @@
   m.WriteCurrentPositionToRegister(1, 0);
   m.Succeed();
   m.Bind(&fail);
   m.Fail();
 
   Handle<String> source = factory->NewStringFromAscii(CStrVector("^foo"));
   Handle<Object> code_object = m.GetCode(source);
   Handle<Code> code = Handle<Code>::cast(code_object);
 
   int captures[4] = {42, 37, 87, 117};
-  const uc16 input_data[6] = {'f', 'o', 'o', 'f', 'o', '\xa0'};
+  const uc16 input_data[6] = {'f', 'o', 'o', 'f', 'o',
+                              static_cast<uc16>('\xa0')};
   Handle<String> input =
       factory->NewStringFromTwoByte(Vector<const uc16>(input_data, 6));
   Handle<SeqTwoByteString> seq_input = Handle<SeqTwoByteString>::cast(input);
   Address start_adr = seq_input->GetCharsAddress();
 
   NativeRegExpMacroAssembler::Result result =
       Execute(*code,
               *input,
               0,
               start_adr,
               start_adr + input->length(),
               captures);
 
   CHECK_EQ(NativeRegExpMacroAssembler::SUCCESS, result);
   CHECK_EQ(0, captures[0]);
   CHECK_EQ(3, captures[1]);
   CHECK_EQ(-1, captures[2]);
   CHECK_EQ(-1, captures[3]);
 
-  const uc16 input_data2[9] = {'b', 'a', 'r', 'b', 'a', 'r', 'b', 'a', '\xa0'};
+  const uc16 input_data2[9] = {'b', 'a', 'r', 'b', 'a', 'r', 'b', 'a',
+                               static_cast<uc16>('\xa0')};
   input = factory->NewStringFromTwoByte(Vector<const uc16>(input_data2, 9));
   seq_input = Handle<SeqTwoByteString>::cast(input);
   start_adr = seq_input->GetCharsAddress();
 
   result = Execute(*code,
                    *input,
                    0,
                    start_adr,
                    start_adr + input->length() * 2,
                    captures);
@@ skipping 953 matching lines @@
     bool in_second = CharacterInSet(&l2, i);
     CHECK((in_first || in_second) == CharacterInSet(&all, i));
   }
 }
 
 
 TEST(Graph) {
   V8::Initialize(NULL);
   Execute("\\b\\w+\\b", false, true, true);
 }