berkeley-db: Avoid failure of HAVE_DB_STAT_ACCEPT_TXN test in
configure

The last argument for db_stat is of type uint32_t, and compilers may
not allow passing NULL in its place.  This causes the check to fail
in some cases where HAVE_DB_STAT_ACCEPT_TXN is expected to be defined,
leading to build failures later.

Submitted upstream: <https://gitlab.com/gnu-clisp/clisp/-/merge_requests/8>

diff --git modules/berkeley-db/configure modules/berkeley-db/configure
index 6f63e605b..c8734a1ca 100755
--- modules/berkeley-db/configure
+++ modules/berkeley-db/configure
@@ -6347,7 +6347,7 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 int
 main (void)
 {
-DB db; db.stat(&db,NULL,0,NULL);
+DB db; db.stat(&db,NULL,0,0);
   ;
   return 0;
 }
diff --git modules/berkeley-db/configure.in modules/berkeley-db/configure.in
index c2b8a5d2d..225fd91b1 100644
--- modules/berkeley-db/configure.in
+++ modules/berkeley-db/configure.in
@@ -38,7 +38,7 @@ AC_CHECK_SIZEOF(db_recno_t,,[#include <stdio.h>
 dnl <http://www.sleepycat.com/docs/ref/upgrade.4.3/stat.html>
 AC_CACHE_CHECK([whether DB->stat() accepts TXNid],ac_cv_db_stat_accept_txn,[
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <db.h>],
-[[DB db; db.stat(&db,NULL,0,NULL);]])],
+[[DB db; db.stat(&db,NULL,0,0);]])],
 ac_cv_db_stat_accept_txn=yes,ac_cv_db_stat_accept_txn=no)])
 if test "$ac_cv_db_stat_accept_txn" = "yes"; then
 AC_DEFINE(HAVE_DB_STAT_ACCEPT_TXN,1,[Define to 1 if DB->stat() accepts TXNid])