title: 'mutex' is not a member of 'std' in MinGW 5.3.0
body: <p>I am using MinGW 5.3.0 and Crypto++ 5.6.5:</p>
  
  <pre><code>C:\MinGW&gt;g++ -std=c++11 -s -D_WIN32_WINNT=0x0501 LOG.cpp -U__STRICT_ANSI__ Decclass.cpp \
  -IC:\\MinGW\\ -IC:\\MinGW\\boost -LC:\\MinGW  -lssl -lcrypto -lcryptopp -lgdi32 -lPCRYPT \
   -lz -ltiny -lwsock32 -lws2_32 -lShlwapi
  </code></pre>
  
  <p>Compiling results in the error below.</p>
  
  <pre><code>c:\mingw\cryptopp565\include\cryptopp\misc.h:287:14: error: 'mutex' in namespace 'std'
  does not name a typestatic std::mutex s_mutex;
  
  c:\mingw\cryptopp565\include\cryptopp\misc.h:296:18: error: 'mutex' is not a member of
  'std'std::lock_guard&lt;std::mutex&gt; lock(s_mutex);
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/bpaBT.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bpaBT.png" alt="enter image description here"></a></p>
  
  <p>It showing <strong>'mutex' is not a member of 'std'</strong> </p>
  
  <p>Do i need anther version of MinGW ? 
  Or can I fix this build itself?    </p>