base.Fatalf("%v", err)
	}
	return b.linkSharedAction(mode, depMode, name, a1)
}

// linkSharedAction takes a grouping action a1 corresponding to a list of built packages
// and returns an action that links them together into a shared library with the name shlib.
// If a1 is nil, shlib should be an absolute path to an existing shared library,
// and then linkSharedAction reads that library to find out the package list.