MacOSX, fink, missing readline/readline.h

This has to do with building postgresql-8.0.3

I'm installing on a MacOSX system (10.3) and configure's failing to
find the readline installation.

output:
checking readline/readline.h usability... yes
checking readline/readline.h presence... no
configure: WARNING: readline/readline.h: accepted by the compiler,
rejected by the preprocessor!
configure: WARNING: readline/readline.h: proceeding with the
preprocessor's result
checking for readline/readline.h... no
checking readline.h usability... no
checking readline.h presence... no
checking for readline.h... no
configure: error: readline header not found

and the config.log extract itself:
configure:7699: gcc -no-cpp-precomp -c -I/sw/include
-I/Library/PostgreSQL8/include -Wall -Wmissing-prototypes
-Wpointer-arith -Wend
if-labels -fno-strict-aliasing conftest.c >&5
configure:7702: $? = 0
configure:7705: test -s conftest.o
configure:7708: $? = 0
configure:7717: result: yes
configure:7721: checking readline/readline.h presence
configure:7728: gcc -no-cpp-precomp -E conftest.c
configure:7724:31: readline/readline.h: No such file or directory
configure:7734: $? = 1
configure: failed program was:
#line 7723 "configure"
#include "confdefs.h"
#include <readline/readline.h>
configure:7752: result: no
configure:7758: WARNING: readline/readline.h: accepted by the compiler,
rejected by the preprocessor!
configure:7760: WARNING: readline/readline.h: proceeding with the
preprocessor's result

This should have worked. The problem is 'gcc -no-cpp-precomp -E'
Is there a solution?
Anything I've tried has failed.

I hope this is an acceptable question to this list - I'm already
inundated with email and more lists will overload me completely.