Change in core[master]: restore --enable-symbols option again -- was FYI: Cleanup of debug options

[Tor Lillqvist]

> the ones who used it have done so for quite a while under the current name...


But surely what we strive for with all of this is not to make things
easier for people who already know what something means, and know that
they want it, or know that they don't want it?

We want to make the meaning of these configure options as
self-documenting as possible to total newbies, right?

--tml