title: __MINGW64__ not defined? Or how do I know what threading model to use?
body: <p>I'm trying to resurrect the windows build of our product, but trying to move over to MingW64 for a better c++ threading experience. But, of course I don't want to just discard the old #include winpthreads code. I'd like an ifdef.</p>
  
  <p>Everything I read says  <strong>MINGW64</strong> should be defined, but eclipse doesn't see it, nor does command-line:</p>
  
  <pre><code>C:\Program Files (x86)\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32&gt;echo | bin\gcc -E -dM - | find "MING"
  #define __MINGW32__ 1
  </code></pre>
  
  <p>So Is this me, or is this the way it is, or am I somehow still seeing my old mingw(32) installation?</p>