61c1f6d7e8
Ideally we should perhaps even error out here; if the user requested building with profiling info, but that profile wasn't found, it seems like the build configuration is subtly broken, and I would expect the user to want to know about it. But that may be a too disruptive change, as users may very well rely on being able to build things in such a setup anyway thanks to Hyrum's Law. To make things clearer, at least print a warning in this case.
See docs/CMake.html for instructions on how to build LLVM with CMake.