The attached patch fixes the problem and allows cross-building the extension modules independently of the configuration of the native interpreter that may have set some modules to be statically built. The patch also prints now the list of modules that are detected by setup.py and configured in one of the Setup files to be statically built into the interpreter.

So you don't need to build from scratch a native interpreter anymore. Can you please test the patch using the Ubuntu interpreter for the cross-build and check that the extension modules are correctly built now.

It's my turn to thank you for your reports and your tests and reactivity that are very helpful in fixing this problem :)