Comment 1 for bug 1810405

I look in my crystal ball and deduce that you're doing this on a filesystem which isn't case-sensitive. This is bug #1714750, and it's really an issue with the u-boot code that we ship a copy of. You can work around it by extracting the sources with "tar xf qemu-2.10.0.tar.xz --exclude qemu-2.10.0/roms/u-boot/scripts/Kconfig" (the file that is excluded isn't needed to build QEMU).

It looks like we never finished the fix for 1714750 -- it's fixed in upstream u-boot but we need to move forward to using that u-boot rather than the one we currently ship.