commit 6b4a144a upstream.

In cross-build environment, we expect to use the cross-compiler objcopy
instead of the host objcopy.

It fixes following build failures:
objcopy --only-keep-debug lib/modules/3.14/kernel/net/ipv6/xfrm6_mode_tunnel.ko /srv/build/linux/debian/dbgtmp/usr/lib/debug/lib/modules/3.14/kernel/net/ipv6/xfrm6_mode_tunnel.ko
objcopy: Unable to recognise the format of the input file `lib/modules/3.14/kernel/net/ipv6/xfrm6_mode_tunnel.ko'
Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Fixes: 810e8437 ('deb-pkg: split debug symbols in their own package')
Reviewed-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>