Building boost.Python fails with non-standard Python installation on Windows

[cschadl]

I'm able to successfully build boost.Python on my local machine with Python 3.13 using b2 like so:

.\bootstrap.bat vc143
.\b2 python=3.13 # other arguments

The issues start happening when I try to build on our Azure DevOps build agents. Because of .*~reasons~*. I can't install Python 3.13 directly on those build agents. So, I zipped up a python 3.13 installation, and in the build pipeline I grab the Python zip file and extract it to some directory, say, Z:\Python313. Then I created a user-config.jam in the root of the boost directory like the following:

using python : 3.13 : Z:\Python313 ;

And in the build pipeline, I try to build boost.Python like so

bootstrap.bat vc143 --with-python=3.13
b2 python=3.13

While bootstrap.bat succeeds, b2 fails with the following error:

error: "3.13" is not a known value of feature <python>
error: legal values: "3.9"

So I understand that the way I'm trying to do this is a little bit unusual, but is there a way that I can get this to work? Or must Python be installed via the installer (because b2 uses py or the registry entries that the installer creates) to build boost.Python on Windows?

[stefanseefeld]

I unfortunately don't have any Windows machine and my understanding of b2 is extremely limited. Perhaps @grafikrobot can help ?