title: Error when bootstrapping CMake:Log of errors
body: <p>To install charmm program I have to install CMake, however, it doesn't install CMake.</p>
  
  <pre><code>[sohyeon@theochem11 cmake-3.15.3]$ ./bootstrap 
  ---------------------------------------------
  CMake 3.15.3, Copyright 2000-2019 Kitware, Inc. and Contributors
  Found GNU toolchain
  C compiler on this system is: gcc       
  ---------------------------------------------
  Error when bootstrapping CMake:
  Cannot find a C++ compiler that supports both C++11 and the specified C++ flags.
  Please specify one using environment variable CXX.
  The C++ flags are "".
  They can be changed using the environment variable CXXFLAGS.
  See cmake_bootstrap.log for compilers attempted.
  ---------------------------------------------
  Log of errors: /export/home/sohyeon/cmake-3.15.3/Bootstrap.cmk/cmake_bootstrap.log
  </code></pre>
  
  <p>so I tried to that script</p>
  
  <pre><code>[sohyeon@theochem11 cmake-3.15.3]$ env CC=cc CXX=CC ./bootstrap
  </code></pre>
  
  <p>But it still occurred same error.</p>
  
  <p>I searched other ways in google. I found this two ways.</p>
  
  <pre><code>$ yum -y install gcc-c++ 
  You need to be root to perform this command.
  
  $ yum install gcc-c++.x86_64 
  You need to be root to perform this command.
  </code></pre>
  
  <p>But it is not solve my problem.</p>
  
  <p>(And I saw cmake_bootstrap.log but I don't know what is wrong.)</p>
  
  <hr>
  
  <p>(Edit)
  Thank you all! </p>
  
  <p>OS version : Linux theochem11.hpc.org 2.6.32-279.14.1.el6.x86_64 #1 SMP Tue Nov 6 23:43:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux</p>
  
  <p>[sohyeon@theochem11 cmake-3.15.3]$ gcc --version
  gcc (GCC) 4.4.6 20120305 (Red Hat 4.4.6-4)
  Copyright (C) 2010 Free Software Foundation, Inc.
  This is free software; see the source for copying conditions.  There is NO
  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.</p>
  
  <p>[sohyeon@theochem11 cmake-3.15.3]$ g++ --version
  g++ (GCC) 4.4.6 20120305 (Red Hat 4.4.6-4)
  Copyright (C) 2010 Free Software Foundation, Inc.
  This is free software; see the source for copying conditions.  There is NO
  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.</p>