When checking whether we need to build libc-hdrgen, we need to check
LLVM_ENABLE_RUNTIMES and RUNTIMES_${target}_LLVM_ENABLE_RUNTIMES, just
the former is not sufficient since libc may be enabled only for certain
targets.
LLVM libc ========= This directory and its subdirectories contain source code for llvm-libc, a retargetable implementation of the C standard library. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.