The attached patch removes special handling of the 'exit tag from
internal_catch.  This special handling was introduced by Alan in commit
Sun Jan 10 20:32:40 2021 +0000
(c7c154bb5756e0ae71d342c5d8aabf725877f186), hence me CC-ing him.

It also exposes Vminibuffer_list to lisp through the new function
Fminibuffer_alist.