+PH/20 Added macros for time_t as for off_t (see PH/15 above) and used them to
+ rework some of the code of TK/09 above to avoid the hardwired use of
+ "%lld" and "long long". Replaced the call to snprintf() with a call to
+ string_vformat().
+
+PH/21 Added another message to those in 4.51/PH/42, namely "All relevant MX
+ records point to non-existent hosts".
+
+PH/22 Fixed some oversights/typos causing bugs when Exim is compiled with
+ experimental DomainKeys support:
+
+ (1) The filter variables $n0-$n9 and $sn0-$sn9 were broken.
+ (2) On an error such as an illegally used "control", the wrong name for
+ the control was given.
+
+ These problems did NOT occur unless DomainKeys support was compiled.
+
+PH/23 Added daemon_startup_retries and daemon_startup_sleep.
+