nscd: Warn when invalid configuration options are selected

[allanjude]

Summary

This is a rebase of the patch from [e-mail] in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=202135

[allanjude]

Fix for keep-hot-count

[markj]

usr.sbin/nscd/parser.c

538 ↗

(On Diff #74328)

It is a bit weird to test what is effectively a bool using > 0. != 0 would be clearer, or just write if (invalid_value) {.

539 ↗

(On Diff #74328)

Missing a space for the continuing line.

[freqlabs]

Agreed, I would have used a bool rather than an int, but this is an improvement regardless.

[allanjude]

usr.sbin/nscd/parser.c

538 ↗

(On Diff #74328)

right.

539 ↗

(On Diff #74328)

This is not actually a continuing line, LOG_ERR_2() is a macro that turns into syslog(LOG_ERR, "nscd error (from %s): %s", sender, ferror);
where the first line is 'sender' and the 2nd line is 'ferror'. Only the 2nd parameter has printf expansion.

[allanjude]

Address review feedback