Remove unnecessary language initializations. Change the main
CMakeLists.txt project() call to specify NONE. Use enable_language(CXX)
instead of project() in cases that need it to avoid enabling C too.
In code such as
install(TARGETS ...
INCLUDES DESTINATION $<FOO>include
)
the generator expressions are evaluated at generate-time. Delay
determining whether each entry is a relative path until after
the generator expressions are evaluated. Such relative paths
are based relative to the CMAKE_INSTALL_PREFIX.