import improvements from HEAD

servers/slapd/back-sql/add.c

servers/slapd/back-sql/back-sql.h

servers/slapd/back-sql/bind.c

servers/slapd/back-sql/compare.c

servers/slapd/back-sql/config.c

servers/slapd/back-sql/delete.c

servers/slapd/back-sql/entry-id.c

servers/slapd/back-sql/external.h

servers/slapd/back-sql/init.c

servers/slapd/back-sql/modrdn.c

servers/slapd/back-sql/proto-sql.h

servers/slapd/back-sql/schema-map.c

servers/slapd/back-sql/search.c

servers/slapd/back-sql/sql-wrap.c

servers/slapd/back-sql/util.c