This change allows a hard coded relative PYTHONHOME setting. So that python can easily be packaged together with lldb.
The change includes:
- Extend LLDB_RELOCATABLE_PYTHON to all platforms. It defaults to ON for platforms other than Windows, to keep the behavior compatible.
- Allows to customize LLDB_PYTHON_HOME. But still defaults to PYTHON_HOME.
- LLDB_PYTHON_HOME can be a path relative to liblldb. If it is relative, we will resolve it before send it to Py_DecodeLocale.