groff/troff burning CPU (spinning?) after upgrade

My buildworld's are now hanging with the following:

cboss:/data/stock/src> ps auxwww -p 11440
USER      PID %CPU %MEM   VSZ  RSS  TT  STAT STARTED      TIME COMMAND
rwatson 11440 45.0  0.3  2420 1728  ??  R     5:01PM  48:38.08 troff
-mtty-char -ms -o1- -Tascii
/data/stock/src/share/doc/papers/beyond4.3/beyond43.ms
cboss:/data/stock/src> ps auxwww -p 24920
USER      PID %CPU %MEM   VSZ  RSS  TT  STAT STARTED      TIME COMMAND
rwatson 24920 45.4  0.3  2420 1728  ??  R     5:36PM  45:26.15 troff
-mtty-char -ms -o1- -Tascii

I've been waiting a while but no relief, suspect strongly they are stuck
in loops of some sort.  CFLAGS in make.conf is -pipe -O; NOPROFILE set,
but otherwise pretty boring build -j 4. 

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert_at_fledge.watson.org      Network Associates Laboratories