Fixes Android build by using C++ math header instead of C one.

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 15668 matching lines @@
 RawDouble* Double::NewCanonical(const String& str) {
   double double_value;
   if (!CStringToDouble(str.ToCString(), str.Length(), &double_value)) {
     return Double::Handle().raw();
   }
   return NewCanonical(double_value);
 }
 
 
 const char* Double::ToCString() const {
-  if (isnan(value())) {
+  if (std::isnan(value())) {
     return "NaN";
   }
-  if (isinf(value())) {
+  if (std::isinf(value())) {
     return value() < 0 ? "-Infinity" : "Infinity";
   }
   const int kBufferSize = 128;
   char* buffer = Isolate::Current()->current_zone()->Alloc<char>(kBufferSize);
   buffer[kBufferSize - 1] = '\0';
   DoubleToCString(value(), buffer, kBufferSize);
   return buffer;
 }
 
 
@@ skipping 3289 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart