title: Autotools check for C++11
body: <p>I use <code>AX_CXX_COMPILE_STDCXX_0X</code>(can look on autoconf-archive) to check for c++11 capabilities of the compiler. It correctly determines that <code>-std=c++0x</code> required, but does not add it to <code>CXXFLAGS</code>. I took a look at the macro source and it actually checks but then restores previous flags.</p>
  
  <p>What should I do to get <code>CXXFLAGS</code> set to be able to compile c++11 source?</p>
  
  <p>Just adding <code>-std=c++0x</code> to <code>AM_CXXFLAGS</code> is not nice solution, because I'd like to put the burden of making the compiler compile in C++11 mode on the autoconf developers, not me.</p>