Building with a bundled libdb changes the names of the exported symbols using
preprocessor magic, so go with it.

--- Linux-PAM-0.99.2.1/configure.in.dbpam	2005-12-15 13:30:30.000000000 +0100
+++ Linux-PAM-0.99.2.1/configure.in	2005-12-15 13:33:05.000000000 +0100
@@ -290,6 +290,11 @@
     AC_CHECK_LIB([db], [db_create], LIBDB="-ldb", LIBDB="")
     LIBS=$BACKUP_LIBS
 fi
+if test -z "$LIBDB" ; then
+    BACKUP_LIBS=$LIBS
+    AC_CHECK_LIB([db], [db_create_pam], LIBDB="-ldb", LIBDB="")
+    LIBS=$BACKUP_LIBS
+fi
 AC_SUBST(LIBDB)
 AM_CONDITIONAL([HAVE_LIBDB], [test ! -z "$LIBDB"])