title: Is there a way to find about with which switches a mingw build is built?
body: <p>Is there a way to find about a specific gcc build that with which switches it is being built?<br>
  I heard that when building a gcc build out of its source code , there are couple of switches which determines some specific features to be available or not e.g there are <code>Thread_posix</code> and/or <code>Win32_thread</code> switches for building <code>MingW</code> on <code>Windows</code>,the first one would allow for using  std::thread and the other would not, or <code>sjlj</code> build vs <code>dwarf</code> builds which deals with exceptions ( i don't even have any idea what they are for! i only know that <code>sjlj</code> build is 15% slower in all cases!)<br>
  So is there away that i can do to know about these and possibly more information in this regard? </p>