* Make CMake find_package(Clang) work. Fixes upstream bug
- Move Clang*.cmake back to /usr/lib/llvm-X.Y/lib/cmake/clang and install a
symlink in /usr/lib/cmake/clang-X.Y.
- Ensure that the LLVM installation prefix is correctly discovered despire
symlinks (replaces fix-cmake-config-prefix.diff).
- Create /usr/lib/llvm-X.Y/bin/clang-X.Y symlink as required by
- Remove useless LLVM_CMAKE_DIR sed command that did not match anything.
- Ignore missing binaries in ClangTargets-relwithdebinfo.cmake.