RFE: a way to abort a long operation (e.g. Ctrl-C / ^C / SIGINT)

[vinc17]

Mutt should have a way to immediately abort an operation because it can take a very long time, e.g. like opening a very large mailbox or doing a limit on the body contents of a very large mailbox. This should probably be done when receiving the SIGINT signal (usually, triggered by Ctrl-C).

If the operation was executed from a macro, the whole macro should terminate. Now, I don't like that very much, as it could prevent some clean-up (like restoring settings). A solution could be a post-interrupt key-sequence for macros...

Note: Ctrl-\ (SIGQUIT) aborts the operation, but also Mutt itself. So, this is a bit too strong.