[OE-core] Why do we allow empty -dev/-dbg packages ?

[ChenQi]

Hi All,

This might be a dummy question, but it has been puzzling me for some 
time. So if someone could give me some explanation, that would be really 
appreciated.

In bitbake.conf, we have:
ALLOW_EMPTY_${PN}-dev = "1"
ALLOW_EMPTY_${PN}-dbg = "1"

That means we allow emtpy -dev/-dbg packages. But what are the benefits 
of these empty -dev/-dbg packages?

Best Regards,
Chen Qi