title: Cmake cannot find compiler
body: <p>I am trying to generate binaries from the source code of the gcc-xml software but when I use Cmake I have this error:</p>
  
  <pre><code>The C compiler identification is unknown
  The CXX compiler identification is unknown
  CMake Error in :
  No CMAKE_C_COMPILER could be found.
  
  
  
  CMake Error in :
  No CMAKE_CXX_COMPILER could be found.
  
  
  
  CMake Warning (dev) in CMakeLists.txt:
  No cmake_minimum_required command is present.  A line of code such as
  
  cmake_minimum_required(VERSION 3.2)
  
  should be added at the top of the file.  The version specified may be     lower
  if you wish to support older CMake versions for this project.  For more
  information run "cmake --help-policy CMP0000".
  This warning is for project developers.  Use -Wno-dev to suppress it.
  </code></pre>
  
  <p>I don't know why I have this error</p>