aad0ae4a39
This addresses the following warning when PYTHON_EXECUTABLE is not set
in the host build:
```bash
CMake Warning:
Manually-specified variables were not used by the project:
PYTHON_EXECUTABLE
```
Reference:
https://github.com/llvm/llvm-project/pull/163574
See docs/CMake.html for instructions on how to build LLVM with CMake.