title: Cmake doesn't honour -D CMAKE_CXX_COMPILER=g++
body: <p>I'm trying to force cmake to build my cpp code with g++, as by default it uses clang instead. So I use: <code>cmake -D CMAKE_CXX_COMPILER=g++ ../src/CMakeLists.txt</code> after which cmake checks for gcc and g++ (with success), but nonetheless <code>make VERBOSE=1</code> yields</p>
  
  <pre><code>/usr/bin/c++     -o CMakeFiles/trial_cpp.dir/trial.cpp.o -c "/Users/Kuba/Code/Sketchpad/Trial     project/src/trial.cpp"
  Linking CXX executable trial_cpp
  /opt/etlocal/bin/cmake -E cmake_link_script CMakeFiles/trial_cpp.dir/link.txt --verbose=1
  /usr/bin/c++    -Wl,-search_paths_first -Wl,-headerpad_max_install_names   CMakeFiles/trial_cpp.dir/trial.cpp.o  -o trial_cpp 
  </code></pre>
  
  <p>As it calls /usr/bin/c++ not /usr/bin/g++ I concur it still uses clang. Any idea what's the problem? I know I have g++ and it's in /usr/bin/.
  I'm running Mac OS X 10.8.2</p>