[O] org-outline-regexp changes break use of org-overview in non-org buffers

[Matt Lundin]

The changes to org-overview in the commit
c3748fcd80ec53dc9b0db6e2ad17be6b14dd3bb9 make it impossible to use
org-global-cycle (i.e., org-overview) in non-org buffers, such as
Auctex.

The problematic line is 6231:

                 (if (re-search-forward org-outline-regexp-bol nil t)

org-outline-regexp-bol is hard-coded to match only the beginning of
outlines in org-buffers:

(defconst org-outline-regexp-bol "^\\*+ ")

The old line in org overview, by contrast, looked for the beginning of
an outline line:

                 (if (re-search-forward (concat "^" outline-regexp) nil t)

Would it be possible to revert to the older, more generous construction
of the regexp (so that it can vary by mode/buffer)?

Thanks!
Matt