alternative, I present .. ta! da! .. the __error() hack.
This patch to the a.out dynamic loader provides old a.out binaries
with __error() if they are linked with an older libc that lacks it,
but are also linked against a library that needs it.
There is a smaller, tricker hack that takes advantage of the fact
that ld.so has __error() too, courtesy of the new libc, but this
hack is the straightforward version.
446517db81