Bug#707091: ld-linux-x32.so.2 --verify segfaults on non-ELF files

[Adam Conrad <adconrad@0c3.net>]

This actually has nothing to do with non-ELF files at all, it's
just that, on an amd64 system, non-ELF files are the only ones
that will trip through trying all ld-linux variants until you
hit the x32 one.

The real problem is that ld-linux-x32 segfaults when run on a
kernel without x32 support.  I had a clever idea a while back
to maybe trap an attempt at some x32-only syscall and exit
gracefully if kernel support is lacking, but haven't found the
time to do that (plus, no matter how lightweight that ends up
being, it still adds a tiny bit of time to every ld.so call on
x32, which is a bit irksome, but possibly worth it to rid us of
the confusing segfaults).

... Adam