Clang 3.4: "libclang can not find the builtin includes. This will cause slow code completion. Please report the problem."

[dunpyl]

Started to get this error after upgrading LLVM + Clang from 3.3 to 3.4. The upgrade was done by installing the 3.4 packages from the official LLVM APT repo on my Xubuntu 13.04 fully patched box.

The issue is similar to #238. I fixed it manually by adding '/usr/lib/llvm-3.4/lib/clang' to the knownPaths list in getBuiltinHeaderPath - as line 35 in libclang.py.

Notice that setting g:clang_library_path cannot fix this problem. Setting it to /usr/lib/llvm-3.4/lib fails the loading of libclang.so, because Config.get_filename() insists on loading it from the location of the designated library_path, which fails because the libclang.so is installed at /usr/lib.