title: C++11 support in GNU automake
body: <p>I'm trying to port buildsystem of my project to GNU autotools. The code need to be compiled with <code>-std=c++11</code> or <code>-std=c++0x</code> flag. I want my configure script to check if compiler supports C++11 or not. I tried adding <code>AX_CHECK_COMPILE_FLAG([-std=c++0x], [CXXFLAGS="$CXXFLAGS -std=c++0x"])</code> to <code>configure.ac</code> file but <code>configure</code> fails with this error:</p>
  
  <pre><code> ...
  ./configure: line 2732: syntax error near unexpected token `-std=c++0x,'
  ./configure: line 2732: `AX_CHECK_COMPILE_FLAG(-std=c++0x, CXXFLAGS="$CXXFLAGS -std=c++0x")'
  </code></pre>