nroff -mandoc | more no longer works

I'm guessing this relates to nroff/groff tweaks, but I was a bit unhappy to 
learn that the command I've used for the last decade to render man pages while 
editing them (nroff -mandoc foo.1 | more) no longer works (output below).

It seems likely this has to do with teaching groff to use ANSI escape codes 
that more, by default, rejects.  I'm aware there are lots of other command 
lines I could use, but it seems unfortunate that this is broken -- possibly 
more should accept more escape codes in its default configuration, or nroff 
should generate fewer of them?

(I'd love to see this fixed for 9.0)

Robert N M Watson
Computer Laboratory
University of Cambridge


robert_at_cinnamon-freebsd:/usr/src/lib/libc/sys> nroff -mandoc dup.2 | more
DUP(2)                    FreeBSD System Calls Manual                   DUP(2)

ESC[1mNAMEESC[0m
      ESC[1mdupESC[22m, ESC[1mdup2 ESC[22m-- duplicate an existing file 
descriptor

ESC[1mLIBRARYESC[0m
      Standard C Library (libc, -lc)

ESC[1mSYNOPSISESC[0m
      ESC[1m#include <unistd.h>ESC[0m

      ESC[4mintESC[0m
      ESC[1mdupESC[22m(ESC[4mintESC[24m ESC[4molddESC[24m);