image_util: use qemu to run native ldconfig

New glibc(glibc 2.16+) does not support generating ld.so.cache for
arm on x86 architectures. This change uses qemu to run native ldconfig
for arm platforms.

BUG=chromium:378377
TEST=the daisy image has the right ld.so.cache with glibc 2.19

Change-Id: Ib0193eda1511031678285facabf6546268f773ce
Reviewed-on: https://chromium-review.googlesource.com/201877
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
4 files changed