Is the problem something like a missing C function prototype? Maybe you see compiler warnings, but the compiler and linker carry on with the wrong prototype. If you build with “make -s”, warnings might be easier to see.

If my guess is right, this would be similar to Issue 27659, where a module half builds with warnings about a missing crypt() function prototype, although it later fails when linking. Maybe more configure or setup.py checks? (I’m not a fan of configure, but it often seems the easiest short-term solution.)