add missing function

Change-Id: I911d1131a91f0a5baea3324c0d48cb4fa5c5c344
order-only dep is enough

Change-Id: Ie040f95a92eb2fc3b68e5310103388a01cfd4fdf
fix deps for PythonTest

System python can be used for build even if the bundled python is
enabled, c.f. --enable-python=internal vs. fully-internal. We need to
use the python that is used at runtime, not for building.

Change-Id: Ia1cd0b787d23645ce469e6975d90f01239256b9b