[CMake] Set LLVM_DEFAULT_EXTERNAL_LIT in standalone build correctly on windows

LLVM installed llvm-lit with a .py suffix on windows. Let's match that
behavior here.

llvm-svn: 356412
1 file changed
tree: 6da7bf069fe51c1cd344883bbd95eaf79a583c1f
  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.