Allow use of system python and lldb

[reporter123]

I have a situation where the built-in python/lldb version is this extension is older than what's on my system. With python particular this causes silent syntax errors in typed scripts loaded via configuration. lldb then aborts processing all costumer formatters in the script and ignores it. lldb when launch from cli will report these errors. That does no good if your extension insists on using its built-in binaries as these don't line up with the system config.