meson: enable full subproject build

Misc changes to the build process and adding wrap-files so that
the full repository can be built as a meson subproject.  This
depends on a few pending changes upstream in phosphor-host-ipmid,
but since that subproject references HEAD it will automatically
resolve as those changes are merged.

Change-Id: Ia3d50e0efa21b07ae4d4886f5930a270976670ed
Signed-off-by: George Liu <liuxiwei@ieisystem.com>
6 files changed