title: Cmake cross compile flags
body: <p>I writing toolchain.cmake file for Linaro toolchain.</p>
  
  <pre><code>include(CMakeForceCompiler)
  set(CMAKE_CROSSCOMPILING   TRUE)
  set(CMAKE_SYSTEM_NAME Linux)
  set(CMAKE_SYSTEM_VERSION 1)
  set(CMAKE_SYSTEM_PROCESSOR "armv7-a")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC -Wno-psabi -frtti -fexceptions" )
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC -Wno-psabi -fexceptions" )
  set(CMAKE_C_COMPILER /home/stranger/linaro/android-toolchain-eabi/bin/arm-linux-androideabi-gcc)
  set(CMAKE_CXX_COMPILER /home/stranger/linaro/android-toolchain-eabi/bin/arm-linux-androideabi-g++)
  CMAKE_FORCE_C_COMPILER("${CMAKE_C_COMPILER}" GNU)
  CMAKE_FORCE_CXX_COMPILER("${CMAKE_CXX_COMPILER}" GNU)
  set(CMAKE_FIND_ROOT_PATH  home/stranger/linaro/android-toolchain-eabi/arm-linux-androideabi)
  include_directories( SYSTEM /home/stranger/android-ndk-r8/platforms/android-14/arch-arm/usr/include)
  include_directories( SYSTEM /home/stranger/android-ndk-r8/sources/cxx-stl/gnu-libstdc++/include)
  include_directories( SYSTEM /home/stranger/android-ndk-r8/sources/cxx-stl/gnu-libstdc++/libs/armeabi-v7a/include)
  </code></pre>
  
  <p>I run cmake:</p>
  
  <pre><code>cmake -DBUILD_ANDROID=On -DCMAKE_TOOLCHAIN_FILE=&lt;path to this toolchain.cmake&gt;  -DCMAKE_BUILD_TYPE=Release &lt;path to my cmake project&gt;
  </code></pre>
  
  <p>But at compile time, i had error about exceptions, instead of defined compiler flags in toolchain file:</p>
  
  <pre><code>error: exception handling disabled, use -fexceptions to enable
  </code></pre>
  
  <p>As far as I can understand my CMAKE_C_FLAGS_RELEASE, CMAKE_CXX_FLAGS_RELEASE has no effect. Why?</p>