I am building LLVM and Clang from the distribution files using CMake, Ninja and gcc 7.1. I can usually get a clean run on this.
I have noticed with Clang 9.0.0 that I get some error messages which seem to be related to a file VCSRevision.h and a search for git. It declares this to be fatal and carries on!
There is very little in the documentation about how to build LLVM and Clang from a distribution as compared to cloning from Git. I am wondering if the build is assuming that git init has been run in the build location.
I have read in the documentation about the CMake variable LLVM_APPEND_VC_REV which is defaulted to ON. Should I be changing this value to OFF?
It would be helpful to have an official manual for building from a distribution along the lines of this unofficial one which I have found to be helpful although now dated: http://chiselapp.com/user/ttmrichter/repository/gng/doc/trunk/output/blog/2016/01-llvm-clang-missing-manual.html