Comment # 21 on bug 1119186 from Aaron Puchert

> Well, that could just as well happen without the %requires_eq, because there
> is no guarantee that Mesa and kdevelop5 would be rebuilt at the same time
> (e.g. kdevelop5 could get an update and being rebuilt against the newer
> version, but Mesa not).
Yes, that doesn't help. I thought about whether an update to llvm6 would have
helped, but then I didn't find anything to update there.

> > Would that be solved if we package the headers with libclang or in a package
> > required by libclang?
> 
> Sure, if libclang(X) contains the headers itself, it's basically
> "guaranteed" that they are available and in the right place.
> That's probably indeed the best way to ensure this.
> No idea if that is a feasible/desirable thing to do (from the clang
> packaging side) though.

I will propose this to the maintainer. I'm maintaining another package
(include-what-you-use) where I have to add a dependency on Clang although the
compiler itself is not needed. It just uses libclang, which needs the builtin
headers to parse code. KDevelop is in a similar situation.