Add build targets for Devil arm deps

Adds build targets for arm versions of md5sum, host_forwarder, and
libc++. Special targets are necessary since the Android/device deps
can't be built with the clang_arm toolchain, so we can't just use it
for everything.

Also updates the arm build config slightly since Raspberry Pis require
mfloat-abi to be set to hard, while Android requires it to be set to
soft.

Bug: 779837
Change-Id: I19c861d2c8a528c82bcb5d9f43c3812499d23ddf
Reviewed-on: https://chromium-review.googlesource.com/761357
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#530711}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: e29eea14f91a8adb8ed3a443fb23eab673f2932b
4 files changed