However, no matter what is done, the path "/System/Library/Frameworks/Kernel.framework/Headers"
is always selected (because there is a sys/xattr.h there), even though NO_DEFAULT_PATH should force
find_path to only search "/usr/include". Adding set(CMAKE_FIND_FRAMEWORK
"NEVER") and set(CMAKE_FIND_APPBUNDLE "NEVER") does not make a difference.
I tried this with many different versions of CMake 3, and this is happening on all of them.