There's a closed pull request on the mblaze repository

mcom: Add sendhook
https://github.com/leahneukirchen/mblaze/pull/226

Description:
This allows to execute commands after a mail has been sent.
Requires a modification of $MBLAZE/profile (new header: `sendhook`).

For now commands with spaces are not allowed, as this would complicate the code.

Closes #204