trouble with autotools/berkeley db

[Lowell Kirsh]

I don't know much about autotools or Berkeley db (bdb) but they are 
being used by a program I'm trying to compile and it's causing me 
problems. The line which is the culprit is in a configure.ac file and it's:

AC_CHECK_LIB(db, db_create, ,AC_MSG_ERROR([Berkeley db library not found]))

This is what ends up causing the configure script to fail. The thing is, 
I am pretty sure I have the newest bdb installed on my system. I am able 
to compile the following bdb-dependent file, which I would think is a 
sign that I have bdb installed:

#include <db.h>
int main() { db_create(0,0,0); }

So to test it out, I read an autotools tutorial and created a tiny 
configure.ac file:

AC_INIT(dbtest.c)
AC_CHECK_LIB(db, db_create, ,AC_MSG_ERROR([Berkeley db library not found]))

This generates a configure file which fails with the following message:

checking for db_create in -ldb... no
configure: error: Berkeley db library not found

Anyone have any idea what's the matter? By the way, I'm running Ubuntu 
Linux.

Thanks in advance,
Lowell