> I cannot see documentation that says the --enable-exportlibs was 
> removed. Since v9_9 is still in use, maybe should document that 
> --enable-exportlibs switch is removed so when some migrate away from 9.9 
> they will have heads up? (But doesn't matter much.)

It would just be listed as an unknown switch when you run configure,
it wouldn't cause a failure.

> doc/arm/libdns.xml still mentions it on master and v9_10.

Let's remove that.