title: Set in cmake for VS "not using precompiled headers"
body: <p>I'm using visual studio 2013 with a compiler option /MP, which doesn't support precompiled headers. How do I set in CMakeLists.txt the "not using precompiled headers"?</p>
  
  <p>EDIT: Resolved.</p>
  
  <p>Mario made me thinking, and I checked again my cmakelists and it seems that I missed an include(./pch_support.cmake). Sorry, I didn't write this thing, and I only added to it the /MP (Multi-processor compilation), which, according to the MSDN doc might collide with other switches such as the precompiled header and create garbled output. Originally, I thought to disable the pch due to an annoying error which I got sometimes, which required a solution rebuild:</p>
  
  <pre><code>"error C1027: Inconsistent values for /Ym between creation and use of precompiled header"
  </code></pre>
  
  <p>But so far, it seems that adding the following lines to cmakelists helped:</p>
  
  <pre><code>string (REPLACE "/Zm1000" "/Zm200" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
  </code></pre>
  
  <p>(but I need more time to determine if it's really a solution, or I need to decide between pch and /MP.)</p>