title: Force CMake to use C++ compiler for C files with Visual Studio
body: <p>I have generated .h and .c files which must be compiled as C++ files with Visual Studio.
  I heard I could do something like <code>set_source_files_properties( ${SOURCES} PROPERTIES LANGUAGE "CXX" )</code>. In parallel, I have read that I should not do that as it should used only in exotic situations.</p>
  
  <p><strong>So, what is the best way to force CMake to generate VS projects which compiles C files as C++ files?</strong></p>
  
  <p>PS: renaming the generated files is not an option.</p>