title: OSX 10.10 CMake 3.0.2 and clang won't find local headers
body: <p>On OSX 10.9 I had installed a variety of header libraries under</p>
  
  <pre><code>/usr/include
  /usr/local/include
  </code></pre>
  
  <p>And everything worked fine.
  Today I did the "free upgrade" to Yosemite, and suddenly everything stopped working.
  Together with Yosemite, I also (previously) upgraded Xcode (note, I am not compiling using Xcode, but clang directly via command line).</p>
  
  <p>I have a CMakeLists.txt which clearly includes /usr/include</p>
  
  <pre><code>set(INCLUDE_HEADERS ${INCLUDE_HEADERS}
               /usr/include
               /usr/local/include)
  include_directories(SYSTEM ${INCLUDE_HEADERS})
  </code></pre>
  
  <p>Yet, when I try to compile, I instantly get:</p>
  
  <pre><code>fatal error: 'boost/lexical_cast.hpp' file not found
  #include &lt;boost/lexical_cast.hpp&gt;
  </code></pre>
  
  <p>What's going on here? Anyone else experience this, or even know how to solve it?
  Things were working fine in 10.9 (oh why did I upgrade?)
  I may also be doing something wrong as I noticed that cmake was upgraded to 3.0.2</p>