Use std:: on symbols declared in C++-style C headers.

test/cctest/test-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 17647 matching lines @@
   i::OS::MemCopy(&target, &value, sizeof(target));
   return target;
 }
 
 
 static double DoubleToDateTime(double input) {
   double date_limit = 864e13;
   if (std::isnan(input) || input < -date_limit || input > date_limit) {
     return i::OS::nan_value();
   }
-  return (input < 0) ? -(floor(-input)) : floor(input);
+  return (input < 0) ? -(std::floor(-input)) : std::floor(input);
 }
 
 
 // We don't have a consistent way to write 64-bit constants syntactically, so we
 // split them into two 32-bit constants and combine them programmatically.
 static double DoubleFromBits(uint32_t high_bits, uint32_t low_bits) {
   return DoubleFromBits((static_cast<uint64_t>(high_bits) << 32) | low_bits);
 }
 
 
@@ skipping 3793 matching lines @@
   }
   for (int i = 0; i < runs; i++) {
     Local<String> expected;
     if (i != 0) {
       CHECK_EQ(v8_str("escape value"), values[i]);
     } else {
       CHECK(values[i].IsEmpty());
     }
   }
 }