title: Error: This compiler appears to be too old to be supported by Eigen
body: <p>I am trying to compile a project that includes the eigen library and I get this error:</p>
  <pre><code>In file included from /home/--/--/--/Eigen/Core:19,
               from /home/--/--/--/Eigen/Geometry:11,
               from /usr/include/rl-0.7.0/rl/math/Transform.h:34,
               from /home/--/--/--/example.cpp:2:
  /home/--/--/--/Eigen/src/Core/util/Macros.h:674:2: error: #error This compiler appears to be too old to be supported by Eigen
  674 | #error This compiler appears to be too old to be supported by Eigen
    |  ^~~~~
  </code></pre>
  <p>I am using:</p>
  <ul>
  <li>Ubuntu 20.04</li>
  <li>Cmake 3.16.3</li>
  <li>VSCode Compiler GCC 10.3.1</li>
  <li>Eigen 3.4.90</li>
  </ul>
  <p>The problem seems to be related to these lines in Macros.h file:</p>
  <pre><code>// The macros EIGEN_HAS_CXX?? defines a rough estimate of available c++ features
  // but in practice we should not rely on them but rather on the availability of
  // individual features as defined later.
  // This is why there is no EIGEN_HAS_CXX17.
  #if EIGEN_MAX_CPP_VER&lt;14 || EIGEN_COMP_CXXVER&lt;14 || (EIGEN_COMP_MSVC &amp;&amp; EIGEN_COMP_MSVC &lt; 1900) || \
     (EIGEN_COMP_ICC &amp;&amp; EIGEN_COMP_ICC &lt; 1500) || (EIGEN_COMP_NVCC &amp;&amp; EIGEN_COMP_NVCC &lt; 80000) ||     \
     (EIGEN_COMP_CLANG &amp;&amp; ((EIGEN_COMP_CLANG&lt;309) || (defined(__apple_build_version__) &amp;&amp; (__apple_build_version__ &lt; 9000000)))) || \
     (EIGEN_COMP_GNUC_STRICT &amp;&amp; EIGEN_COMP_GNUC&lt;51)
  #error This compiler appears to be too old to be supported by Eigen
  #endif
  </code></pre>
  <p>Do you know how to fix this error?</p>