/usr/lib/clang/3.9/include is in libclang-common-3.9-dev 1:3.9.1-9.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/clang/3.9/../../llvm-3.9/lib/clang/3.9.1/include
/usr/lib/clang/3.9/../../llvm-3.9/lib/clang/3.9.1/include