@michalsrb: If you don't like the %{_relver} -> %{_sonum} renaming, I can revert that. I just found it easier to read (and type) and there is no real need for the full version, unless we want to support llvm* as multiversion package. I sometimes need multiple major versions installed at the same time, but I haven't found myself in need of installing llvm7 7.0.0 and 7.0.1 next to each other.

Another thing: it came up in boo#1119186 that applications using libclang (such as KDevelop or include-what-you-use) typically need the builtin headers in /usr/lib64/clang/..* that are currently packaged in clang. So these applications have a dependency on clang, although they actually only need the headers that come with it. Would it be Ok if we either package the headers with libclang, or make a separate package that libclang depends on? I don't think that libclang is of any use without these headers, since you can't sensibly parse any code without them. And it wouldn't break anything, since clang depends on libclang, so it would still get the headers.

@michalsrb: review reminder