title: GCC/G++ : Enable -std=c++11 from environment variable
body: <p>I have some OpenCV/C++ application which compiles with a CMake definitions file, in which I did not find a way to pass flags to the compiler.</p>
  
  <p>I know that there are the flags C_INCLUDE_PATH CPLUS_INCLUDE_PATH, and all the rest of their friends... </p>
  
  <p>But, is there an environment variable for definition of any other flags, in which I'd be able to define <code>-std=c++11</code> ?</p>