need for 'dynamical-let'?

[Stephen Leake]

I'm switching on lexical-binding in some files.

In several cases, the byte compiler is complaining:

xgit.el:993:30:Error: add-to-list cannot use lexical var `branch-list'

So I have to change code like this:

(let (branch-list
      ...)
   (add-to-list branch-list (substring branch-entry 2) t)


to:

(defvar dvc-branch-list);; add-to-list can't use lexical var
(let (
      ...)
   (add-to-list 'dvc-branch-list (substring branch-entry 2) t)


This pollutes the global name space, and disguises the local nature of
'branch-list'.

Can we define a macro 'dynamical-let' that would implement this
pattern, but with hidden variables?

-- 
-- Stephe