It's not theoretical. I invite you to install a cross-compiler and try it.
Sure. By theoretical I meant "because so few people cross-compile". (And even fewer modify the sources. And even fewer than that care that help2man might fail. I think we might be down to one person in the world. :) Here's a patch that is even simpler, touching only the configure.ac file. Well, that seems the simplest solution yet. I guess it is worth complicating configure.ac in this way for the sake of correctness, although it still seems a shame somehow. Thanks, Karl