Re: consider -Wmissing-variable-declarations

Here is an updated patch set. I have implemented proper solutions for
the various hacks in the previous patch set. So this patch set should
now be ready for proper consideration.

The way I have organized it here is that patches 0002 through 0008
should be improvements in their own right.

The remaining two patches 0009 and 0010 are workarounds that are just
necessary to satisfy -Wmissing-variable-declarations. I haven't made up
my mind if I'd want to take the bison patch 0010 like this and undo it
later if we move to pure parsers everywhere, or instead wait for the
pure parsers to arrive before we install -Wmissing-variable-declarations
for everyone.

Obviously, people might also have opinions on some details of where
exactly to put the declarations etc. I have tried to follow existing
patterns as much as possible, but those are also not necessarily great
in all cases.