This improves the compatibility and makes it easier to work with various tools,
which take advantake from the assumption of existence of those labels.
Keep the old labels for selectors for backward compatibility.
Also note there is slight change in behaviour of PDB which might
be backward-incompatible in some rare cases.
Jiří Pinkava
Vincent Mizoules
Muneeb Aijaz
Mikhail Koniakhin
yangtian9999
Patrick Spies