Hardcoded MAILFMT not compatible with busybox sendmail

[glensc]

the MAILFMT is hardcoded to source as AC_DEFINE(MAILFMT,"%s -FCronDaemon -i -odi -oem -oi -t -f %s",:

• https://github.com/cronie-crond/cronie/blob/cronie-1.5.4/configure.ac#L201-L209

and the -Fx = Set full-name of sender option is not recognized by busybox-v1.30.0:

/usr/lib/sendmail: invalid option -- 'F'
BusyBox v1.30.0 (2019-01-24 15:23:24 CET) multi-call binary.
...

https://github.com/cronie-crond/cronie/blob/cronie-1.5.4/src/do_command.c#L430

[glensc]

EDIT: looks like it is tunable via -m option, but the solution lacks %s templating for mailfrom:

• https://github.com/cronie-crond/cronie/blob/cronie-1.5.4/src/do_command.c#L430
• https://github.com/cronie-crond/cronie/blob/cronie-1.5.4/src/do_command.c#L437