CMake Error at NonValidTarget-C_COMPILER_VERSION.cmake:1 \(add_custom_command\):
  Error evaluating generator expression:

    \$<C_COMPILER_VERSION>

  \$<C_COMPILER_VERSION> may only be used with binary targets.  It may not be
  used with add_custom_command or add_custom_target.
Call Stack \(most recent call first\):
  CMakeLists.txt:3 \(include\)