[CMake] Add error to clarify that lldb requires libcxx

Summary:
This adds a specific error message to clarify that lldb requires libcxx when
built together with clang on macOS. In addition, the lldb building docs are also
updated.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41866

Reviewers: sgraenitz, JDevlieghere, EricWF

Reviewed By: sgraenitz

Subscribers: mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D61877

llvm-svn: 360756
2 files changed
tree: 04d5a5193e2d4b9397f26f82baeaf3d2f7830e2a
  1. .arcconfig
  2. .clang-format
  3. .clang-tidy
  4. .gitignore
  5. README.md
  6. clang-tools-extra/
  7. clang/
  8. compiler-rt/
  9. debuginfo-tests/
  10. libclc/
  11. libcxx/
  12. libcxxabi/
  13. libunwind/
  14. lld/
  15. lldb/
  16. llgo/
  17. llvm/
  18. openmp/
  19. parallel-libs/
  20. polly/
  21. pstl/
README.md

The LLVM Compiler Infrastructure

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