Thanks for the report. Unfortunately, as far as I know, we don't claim anywhere to support cross-compiling in general.  As you've probably noticed, the Python Makefile-based build system (for non-Windows platforms) is by no means a conventional GNU autotools one. Over the years there have been some efforts to add support for a handful of specific cross-compilation scenarios, for example compiling for Android.  But I'm afraid you are more or less on your own for the case here.  That said, if you or someone else is motivated to supply some fixes to make more cross-compiling cases work, feel free to reopen the issue and submit the fixes as PRs and they may be considered.  What would probably be the best would be to try to reimplement our build system from the ground up with modern Autotools or something similar but that's a *really* big deal.