title: error: 'mutex' does not name a type
body: <p>When I am try the following code in ubuntu with arm-none-eabi-g++ tool chain i was getting compilation errors:</p>
  
  <pre><code>#include &lt;iostream&gt;  
  #include  &lt;thread&gt;    // std::thread    
  #include  &lt;mutex&gt;    // std::mutex    
  mutex mtx;           // mutex for critical section
  
  int main ()
  {
      return 0;
  }
  </code></pre>
  
  <p>commpile command :</p>
  
  <pre><code>arm-none-eabi-g++ -Os -Wall -std=c++11 -fno-rtti -fno-exceptions -c mt.cc
  </code></pre>
  
  <p>compile error:</p>
  
  <blockquote>
    <p>mt.cc:5:1: error: 'mutex' does not name a type mutex mtx;           //
    mutex for critical section</p>
  </blockquote>
  
  <p>^</p>
  
  <p>gcc version:</p>
  
  <p>gcc version 4.8.4 20140725 (release) [ARM/embedded-4_8-branch revision 213147] (GNU Tools for ARM Embedded Processors)</p>