MFC r294506:

Prevent loader.conf load failure due to unknown console entries

Sponsored by: Multiplay

MFC r276079, r276087:

Add a divisor parameter to twiddle() so that callers can request that
output only happen on every Nth call.

Add a new loader(8) variable, twiddle_divisor, allowing control over the
output frequency of the "twiddle" IO progress indicator.

MFC r276079, r276087:

Add a divisor parameter to twiddle() so that callers can request that
output only happen on every Nth call.

Add a new loader(8) variable, twiddle_divisor, allowing control over the
output frequency of the "twiddle" IO progress indicator.