CMake Error at BadSources2.cmake:[0-9]+ \(try_compile\):
  Unknown extension ".cxx" for file

    .*/Tests/RunCMake/try_compile/src.cxx

  try_compile\(\) works only for enabled languages.  Currently these are:

    C NONE( RC)?

  See project\(\) command to enable other languages.
Call Stack \(most recent call first\):
  CMakeLists.txt:3 \(include\)