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

runtime/lib/double.cc

 // Copyright (c) 2011, 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 <math.h>
+#include "vm/bootstrap_natives.h"
 
-#include "vm/bootstrap_natives.h"
+#include "platform/math.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/code_generator.h"  // DartModulo.
 #include "vm/double_conversion.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/symbols.h"
 
 namespace dart {
@@ skipping 253 matching lines @@
 DEFINE_NATIVE_ENTRY(Double_getIsNegative, 1) {
   const Double& arg = Double::CheckedHandle(arguments->NativeArgAt(0));
   // Include negative zero, infinity.
   double dval = arg.value();
   return Bool::Get(signbit(dval) && !isnan(dval)).raw();
 }
 
 // Add here only functions using/referring to old-style casts.
 
 }  // namespace dart