Alan Modra wrote:
> IBM legal get back to me to say they believe IBM's FSF copyright
> assignment letter does cover contributions to EMACS.

This should be enough. I installed your patch into Emacs master, with one minor 
fixup (attached) to pacify './configure --enable-gcc-warnings'.

Petr, can you please verify that this fixes the bug for you? If so, I can mark 
the bug as fixed in our database.

Thanks again for fixing the bug, Alan.