Always specify the preDistPhases attribute as a list instead of a string.
Append elements to the preDistPhases Bash variable using appendToVar
instead of string or Bash array concatenation.
Handle element insertion before a specific element using string
substitution as before, but handle both structured and unstructured
attributes.
checkInputs used to be added to nativeBuildInputs. Now we have
nativeCheckInputs to do that instead. Doing this treewide change allows
to keep hashes identical to before the introduction of
nativeCheckInputs.