Clang Compile error with default initialization

Consider following example:

#include <iostream>
#include <type_traits>

struct A
{
  //A() = default; // does neither compile with, nor without this line
  //A(){};         // does compile with this line
  int someVal{ 123 };


  void foobar( int )
  {
  };
};


int main()
{
    const A a;
    std::cout << "isPOD = " << std::is_pod<A>::value << std::endl;
    std::cout << "a.someVal = " <<a.someVal << std::endl;
}

See Live example

This does compile with g++ but does not compile with clang++, tried with following command: 'clang++ -std=c++11 -O0 main.cpp && ./a.out'

Compile error from clang: main.cpp:19:13: error: default initialization of an object of const type 'const A' requires a user-provided default constructor

I learned from This Stack Overflow Question, that non-POD classes get default constructor. This is even not necessary here because the variable has c++11-style default initialization

Why does this not for clang? Why does 'A() = default;' not work, too?