Hi all,

* lisp/org-src.el (org-src-font-lock-fontify-block): Reset the
modification flag of the temporary fontification buffer after
fontifying.

Without this some modes cause Emacs to prompt about unsaved buffers
when exiting: `Save buffer *org-src-fontification:...-mode*?'

(I'm seeing this with Proof General's coq-mode, specifically.)

Clément.