90a9f65b8d
To fix #8106, we need an LLVM version that contains r211082 aka 0dee6756 which fixes a bug that blocks that issue. There have been some tiny API changes in LLVM, and cmpxchg changed its return type. The i1 part of the new return type is only interesting when using the new weak cmpxchg, which we don't do.
This directory currently contains some LLVM support code. This will generally be sent upstream to LLVM in time; for now it lives here.