primegen: @0.97: nroff: command not found

[ryandesign (Ryan Carsten Schmidt)]

primegen fails to build on Ventura and later.

​https://build.macports.org/builders/ports-14_x86_64-builder/builds/27184/steps/install-port/logs/stdio

make: Entering directory `/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_math_primegen/primegen/work/primegen-0.97'
nroff -man primes.1 > primes.0
nroff -man primespeed.1 > primespeed.0
nroff -man primegaps.1 > primegaps.0
nroff -man primegen.3 > primegen.0
( cat warn-auto.sh; \
	echo CC=\'`head -1 conf-cc`\'; \
	echo LD=\'`head -1 conf-ld`\' \
	) > auto-ccld.sh
sed s/conf-words/`head -1 conf-words`/ \
	< primegen.h.sed > primegen.h
cat auto-ccld.sh make-load.sh > make-load
cat auto-ccld.sh find-systype.sh > find-systype
cat auto-ccld.sh make-compile.sh > make-compile
cat auto-ccld.sh make-makelib.sh > make-makelib
/bin/sh: nroff: command not found
make: *** [primes.0] Error 127
make: *** Waiting for unfinished jobs....
/bin/sh: nroff: command not found
make: *** [primegen.0] Error 127
/bin/sh: nroff: command not found
/bin/sh: nroff: command not found
chmod 755 make-makelib
chmod 755 make-compile
chmod 755 find-systype
chmod 755 make-load
make: *** [primegaps.0] Error 127
make: *** [primespeed.0] Error 127
make: Leaving directory `/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_math_primegen/primegen/work/primegen-0.97'
Command failed:  cd "/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_math_primegen/primegen/work/primegen-0.97" && /usr/bin/make -j8 -w it 

[toy]

As far as I understood adding depends_build bin:nroff:groff or depends_build bin:nroff:heirloom-doctools will resolve this. But as they are conflicting ports, for people having the other installed it will be an annoying installation (deactivate the other port, install primegen, reactivate the other port), or the build dependency is not activated?