let-bind a varlist only known at run time

[Roland Winkler]

Normally the varlist for the special let form is hardcoded.  Is it
possible to specify the varlist only at runtime?

The usage scenario I have in mind is that a user variable foo-alist
may hold an alist that becomes the varlist for the let-binding.  So
it's not known at compile time which bindings a user might want to
specify in foo-alist.  Also, it might be hard to predict an
exhaustive list of "candidate variables" a user might want to put into
foo-alist (and certainly such a list would be hard to maintain).

On the other hand, I expect that efficiency is not an issue for the
body appearing in let.  So if there is nothing else I could
construct the complete let-form at runtime and pass it on to `eval'.
But maybe there is a better solution...

Thanks!

Roland