Some systems define a type for sys_errlist[ ] that differs from the internal declaration made by sendmail. In such instances you will get a warning about sys_errlist being redefined when you compile. Such warnings are usually harmless, but they are unattractive. To eliminate them, add the following to your Build m4 file:

APPENDDEF(`confENVDEF', `-DERRLIST_PREDEFINED')

When porting to a new system, you can test with the preceding confENVDEF build macro statement and, if successful, put a permanent porting entry into sendmail/conf.h. New ports should be reported to sendmail@sendmail.org so that they can be folded into future releases.