While nosing around princ and friends, I wondered if princ-list could
use mapc these days, per below.

I suppose the byte code comes out about the same, but `mapc' on a small
fixed-length list might in the future have a chance of being optimized
to individual calls to , save some looping ops.  (Presuming princ-list
remains a defsubst so it expands.  Personally I'd have been tempted not
to bother inlining it.)