title: version GLIBC_PRIVATE not defined in file ld-linux-x86-64.so.2
body: <p>if anyone could give a beginner some help on gcc version issue?</p>
  
  <p>I met the issue on <code>"version GLIBCXX_3.4.20' not found"</code>. After I followed the link: <a href="https://stackoverflow.com/questions/36327805/how-to-install-gcc-5-3-with-yum-on-centos-7-2">How to Install gcc 5.3 with yum on CentOS 7.2?</a>
  I met extra issues as below:</p>
  
  <pre><code>scl enable devtoolset-7 bash
  git: relocation error: libc.so.6: symbol _dl_starting_up, version GLIBC_PRIVATE not defined in file ld-linux-x86-64.so.2 with link time reference 
  </code></pre>