/usr/lib/clang/5.0/include is in libclang-common-5.0-dev 1:5.0.1-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/clang/5.0/../../llvm-5.0/lib/clang/5.0.1/include
/usr/lib/clang/5.0/../../llvm-5.0/lib/clang/5.0.1/include