package: Fix darwin shlibs code

We need to scan binaries as well as libraries for dependencies.

Also ensure if its not an object file (as found by otool), we handle
this case.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
autotools: Exclude SDK_OS from autotools task signatures

The change to handle SDKs of different types resulted in the signatures
becoming SDK specific which wasn't intended. Exclude the variable from the
hash values to avoid this.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>