How to list library dependencies of a non-native binary?

is there any way to get a list of the dynamically linked dependency for of a foreign binary

You can list direct dependencies of a binary easily enough:

readelf -d a.out | grep NEEDED

 0x0000000000000001 (NEEDED)             Shared library: [librt.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]

I know of no way to recursively continue this to get the full list (as ldd does). You’ll have to repeat the process for every NEEDED library by hand.