gn build: Add some build files for clangd

Enough to build the clangd binaries, but this is still missing build
files for:
- fuzzer
- indexer
- index/dex/dexp
- benchmarks
- xpc

Differential Revision: https://reviews.llvm.org/D59899

llvm-svn: 357182
7 files changed
tree: fa062d885a72b3732ae5d4dfafaa8a637e2df119
  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. pstl/
  17. .arcconfig
  18. .clang-format
  19. .clang-tidy
  20. README.md
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.