Got this error trying to build criu on ppc64le under qemu, after
updating the Dockerfile to use Ubuntu Xenial (rather than Trusty):

> $ rm -rf .ccache; make -C scripts/build ppc64le-clang
>
> ...
>
> Processing triggers for libc-bin (2.24-9ubuntu2.2) ...
> /sbin/ldconfig.real: 1: /sbin/ldconfig.real: Syntax error: "(" unexpected
> /sbin/ldconfig.real: 1: /sbin/ldconfig.real: Syntax error: "(" unexpected
> dpkg: error processing package libc-bin (--configure):
>  subprocess installed post-installation script returned error exit status 2
> ...

Apparently, ldconfig.real binary header differs from others:

root@3c7593d3298d:/# od -x /bin/ls | head -2
0000000 457f 464c 0102 0001 0000 0000 0000 0000
0000020 0002 0015 0001 0000 5680 1000 0000 0000

root@3c7593d3298d:/# od -x /sbin/ldconfig.real | head -2
0000000 457f 464c 0102 0301 0000 0000 0000 0000
0000020 0002 0015 0001 0000 1d58 1000 0000 0000

Amend the mask in binfmt_misc entry to take this into account.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>