This reverts commit bec8a372fc0db95852748691c0f4933044026b25. This causes many of these errors to appear when rebuilding runtimes part of fuchsia's toolchain: ld.lld: error: /usr/local/google/home/paulkirth/llvm-upstream/build/lib/x86_64-unknown-linux-gnu/libunwind.a(libunwind.cpp.o) is incompatible with elf64-x86-64 This can be reproduced by making a complete toolchain, saving any source file with no changes, then rerunning ninja distribution.
See docs/CMake.html for instructions on how to build LLVM with CMake.