[CMake] Support builtins as Clang default rtlib in compiler-rt

Use compiler-rt builtins when selected as default Clang rtlib and avoid
explicitly passing -rtlib= flag to avoid the "argument unused during
compilation" warning.

This is a partial alternative to D47094 that does not rely on compiler
runtime checks.

Differential Revision: https://reviews.llvm.org/D47115

llvm-svn: 333037
2 files changed
tree: 34b6833d19b02957d7ac63845184ee626ee7dead
  1. clang/
  2. clang-tools-extra/
  3. compiler-rt/
  4. debuginfo-tests/
  5. libclc/
  6. libcxx/
  7. libcxxabi/
  8. libunwind/
  9. lld/
  10. lldb/
  11. llgo/
  12. llvm/
  13. openmp/
  14. parallel-libs/
  15. polly/
  16. README.md
README.md

Low Level Virtual Machine (LLVM)

This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.