Here is an implementation of *default-special-bindings*, with a test.

I opted for thunks instead of forms to eval because eval is evil. They are called in the new thread; changing this is trivial by changing the binding-default-specials function used by all backends.

However, I won't be using it for fluid-database (http://repo.or.cz/w/clsql/s11.git?a=shortlog;h=refs/heads/fluid-pools), because ht-fluids are easier to use and have a better guarantee of availability and finalization.