Bugzilla:Speed Up Sendmail

On bugzilla.mozilla.org, we recently got a HUGE performance boost on making bug changes by configuring Sendmail's command-line submission tool to background itself after getting the email from Bugzilla instead of trying to deliver it to the main sendmail daemon while Bugzilla waits for it. We thought we had it hacked this way already, but it turned out it didn't work, because FEATURE('msp') overrides the delivery mode, so you have to override it back after the FEATURE('msp') line. Here's what our submit.mc file for sendmail looks like:

include(`/usr/share/sendmail-cf/m4/cf.m4')
VERSIONID(`linux setup for Red Hat Linux')dnl
define(`confCF_VERSION', `Submit')dnl
define(`__OSTYPE__',`')dnl dirty hack to keep proto.m4 from complaining
define(`_USE_DECNET_SYNTAX_', `1')dnl support DECnet
define(`confTIME_ZONE', `USE_TZ')dnl
define(`confDONT_INIT_GROUPS', `True')dnl
define(`confPID_FILE', `/var/run/sm-client.pid')dnl
define(`confDIRECT_SUBMISSION_MODIFIERS',`uAC')
define(`confTO_IDENT', `0s')dnl
FEATURE(`nocanonify')dnl
FEATURE(`accept_unresolvable_domains')dnl
FEATURE(`accept_unqualified_senders')dnl
FEATURE(`use_ct_file')dnl
dnl
dnl If you use IPv6 only, change [127.0.0.1] to [IPv6:::1]
FEATURE(`msp', `[127.0.0.1]')dnl
define(`confDELIVERY_MODE',`b')dnl This has to be *after* FEATURE('msp') or it won't work