CMake Warning at source_subfolder/CMakeLists.txt:63 (message): GNU/GCC VERSION LESS THAN 5, ENABLING COMPATIBILITY MODE. CMake Warning: Manually-specified variables were not used by the project: CMAKE_EXPORT_NO_PACKAGE_REGISTRY CMAKE_INSTALL_BINDIR CMAKE_INSTALL_DATAROOTDIR CMAKE_INSTALL_INCLUDEDIR CMAKE_INSTALL_LIBDIR CMAKE_INSTALL_LIBEXECDIR CMAKE_INSTALL_OLDINCLUDEDIR CMAKE_INSTALL_SBINDIR CMake Warning: Manually-specified variables were not used by the project: CMAKE_EXPORT_NO_PACKAGE_REGISTRY