groff macro package 'mom' not installed

[Francesco Casadei]

$ uname -a
FreeBSD goku.kasby 4.9-STABLE FreeBSD 4.9-STABLE #0: Fri Oct 31 09:49:25
CET 2003     root at goku.kasby:/usr/obj/usr/src/sys/GOKU  i386

$ echo 'Hello world!' > hw.t
$ groff -Tps -ms hw.t > hw.ps
$ file hw.ps
hw.ps: PostScript document text conforming at level 3.0
$ groff -Tps -mom hw.t > hw.ps
troff: fatal error: can't find macro file om
$ groff -Tps -m mom hw.t > hw.ps
troff: fatal error: can't find macro file mom
$ man groff
[snip]
SEE ALSO
[snip]
   Groff macro packages and macro-specific utilities:
      groff_tmac(5),    groff_man(7),    groff_mdoc(7), groff_me(7),
      groff_mm(7),    groff_mmse(7),    groff_mom(7), groff_ms(7),
      groff_www(7), groff_trace(7), mmroff(7).

$ man groff_mom
No manual entry for groff_mom
$ man 7 groff_mom
No entry for groff_mom in section 7 of the manual

$ ls /usr/src/contrib/groff/contrib/mom
BUGS          NEWS          examples      momdoc
ChangeLog     TODO          groff_mom.man om.tmac
Makefile.sub  copyright     mom.tmac

Why did the mom macro package not get installed with the
buildworld/installword procedure? I tried to run configure followed by
make in /usr/src/contrib/groff, but the latter stopped with error 'don't
know how to make mdoc'.

How do I install the mom macro package?

	Francesco Casadei