Revert "kernel-arch: Always use ld.bfd to link the kernel"

This reverts commit 5652086c75be0eb5e9deac0e3f2b7bd343583838.
Fix packaging errors

Note that this is a hack.  The meta-sourcery layer does this
properly.

Modified version of the following:
  https://github.com/MentorEmbedded/meta-sourcery/commit/7bf1138a013c50ce37ad5efd039009df7182a44e
  https://github.com/MentorEmbedded/meta-sourcery/commit/004c18ac5d5cdd97ada5711b8cf641997059b7cc

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
Only use the '-msgxx-glibc' option with CodeBench Pro

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
Add libquadmath packages

Modified and applied from:
    https://github.com/MentorEmbedded/meta-sourcery/commit/f5e5f74648dde5e95cd77825d608ce07ba946bf7

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
Cleanup some empty dirs to avoid packaging errors
Grab fix from meta-sourcery layer for external toolchain usage.

Commit logs:
    commit f573bdb536b33e87748d6f85a269da6be9f6bba4
    Author: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
    Date:   Tue Jul 17 16:52:34 2012 +0300

        tcmode-external-sourcery: CSL_TARGET_SYS may contain a list of triplets

        The first mentioned toolchain triplet from the list is selected, if
        there is a correspondent compiler found in external toolchain path.

        Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>

    commit e8e350808447ff566bc89792c4a7dac90df79722
    Author: Christopher Larson <chris_larson@mentor.com>
    Date:   Sun Jul 29 13:47:38 2012 -0400

        tcmode-external-sourcery: don't fall back to non-prefixed for CSL_TARGET_SYS

        Signed-off-by: Christopher Larson <chris_larson@mentor.com>

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
Only copy files if the parent directory exists

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
tcmode-external-sourcery: Allow x86_64-linux-gnu as toolchain prefix

Allow x86-64 builds to use x86_64-linux-gnu as the prefix for the
cross tools.

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>