After perl Makefile.PL && make, I get the following errors:

Manifying 
blib/man1/spamproxyd.1
/usr/bin/pod2man: bad option in paragraph 95 of 
spamproxy/spamproxyd: ``-o'' should be [CB]<-o>
/usr/bin/pod2man: bad option in paragraph 95 
of spamproxy/spamproxyd: ``-o'' should be [CB]<-o>
/usr/bin/pod2man: bad option in paragraph 
95 of spamproxy/spamproxyd: ``-o'' should be [CB]<-o>
Manifying 
blib/man1/spamd.1
/usr/bin/pod2man: bad option in paragraph 133 of spamd/spamd: ``-u'' 
should be [CB]<-u>
[...]
Manifying 
blib/man3/Mail::SpamAssassin::Conf.3
/usr/bin/pod2man: bad option in paragraph 300 of 
lib/Mail/SpamAssassin/Conf.pm: ``-D'' should be [CB]<-D>
/usr/bin/pod2man: bad option in 
paragraph 301 of lib/Mail/SpamAssassin/Conf.pm: ``-D'' should be [CB]<-
D>
/usr/bin/pod2man: bad option in paragraph 370 of lib/Mail/SpamAssassin/Conf.pm: ``-R'' 
should be [CB]<-R>

Then, with 'make test':

BEGIN failed--compilation aborted at 
../spamassassin line 5.

For all tests.  I'm running the stock version of perl: 

$ perl -
V
Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    
osname=freebsd, osvers=4.0-current, archname=i386-freebsd
    uname='FreeBSD 
freefall.FreeBSD.org 4.0-current FreeBSD 4.0-current #0: $Date$'
    hint=recommended, 
useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  
Compiler:
    cc='cc', optimize='undef', gccversion=2.95.2 19991024 (release)
    
cppflags=''
    ccflags =''
    stdchar='char', d_stdstdio=undef, usevfork=true
    intsize=4, 
longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, 
d_longdbl=define, longdblsize=12
    alignbytes=4, usemymalloc=n, prototype=define
  
Linker and Libraries:
    ld='cc', ldflags ='-Wl,-E -lperl -lm '
    libpth=/usr/lib
    libs=-lm -lc -
lcrypt
    libc=, so=so, useshrplib=true, libperl=libperl.so.3
  Dynamic Linking:
    
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' -Wl,-R/usr/lib'
    cccdlflags='-
DPIC -fpic', lddlflags='-Wl,-E -shared -lperl -lm '


Characteristics of this binary (from 
libperl):
  Built under freebsd
  Compiled at Jul 13 2002 17:50:05
  @INC:
    
/usr/local/lib/perl5/site_perl/5.005/i386-freebsd
    
/usr/local/lib/perl5/site_perl/5.005
    .
    /usr/libdata/perl/5.00503/mach
    
/usr/libdata/perl/5.00503

It built version 2.11 just fine, and has been running it for some 
time.