Provide buildd as separate Debian package buildd, use nail instead of mutt in buildd for sending mails.
Recent Mutt versions introduced an annoying cmdline behaviour change
in a patch version upgrade (1.5.x->1.5.y) which breaks sending mails
from the cmdline when you've to add several attachments at once
and want to stay backward and forward compatible.
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=539276
for further details.
Therefore get rid of mutt and use nail for sending mails instead.