[EXIM] difficulty

This is the first time I am compiling Exim 2.01, appear to me didnt go
smooth when I just run "make"

following is the error message, which I am not quiet understand
------------------------------------------------------------------------
gcc -o exim  accept.o child.o daemon.o dbfn.o debug.o deliver.o direct.o
directory.o dns.o drtables.o exim.o expand.o filter.o globals.o  header.o
host.o log.o match.o moan.o os.o parse.o queue.o  readconf.o retry.o
rewrite.o route.o search.o smtp_in.o spool_in.o spool_out.o  store.o
string.o tod.o transport.o tree.o verify.o version.o \
     libident/libident.a pcre/libpcre.a directors/directors.a \
     routers/routers.a transports/transports.a lookups/lookups.a \
     -lsocket -lnsl -lkstat    -lresolv \

Undefined                       first referenced
 symbol                             in file
hosts_ctl                           smtp_in.o
ld: fatal: Symbol referencing errors. No output written to exim
*** Error code 1
make: Fatal error: Command failed for target `exim'
Current working directory /usr/share/src/exim-2.01/build-SunOS5-5.6-sparc
*** Error code 1
make: Fatal error: Command failed for target `postmakefile'
Current working directory /usr/share/src/exim-2.01/build-SunOS5-5.6-sparc
*** Error code 1
make: Fatal error: Command failed for target `go'

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