title: passing DCPU_DISPATCH option to theano (disabling dispatched CPU optimization)
body: <p>I'm using theano with anaconda on windows.</p>
  
  <p>I faced "Error: invalid register for .seh_savexmm\r."</p>
  
  <p>From some search, I found out my current problem comes from the dispatched CPU optimization when theano tries to build the code with GCC (I'm using minGW)</p>
  
  <p>Disabling Dispatched CPU optimizations by passing the -DCPU_DISPATCH= flag to CMake would solve the problem.</p>
  
  <p>I'm looking at conda-build and conda-forge, but it is very hard to figure out how to pass the option.</p>
  
  <p>Could you please advise me of how to pass the build option?</p>
  
  <p>Thank you.</p>