Issue title: mosquitto 1.6.9-0mosquitto1~bionic1 in ubuntu bionic PPA not available due to build failure
 Issue body: At this time, mosquitto 1.6.9 is not available from the Ubuntu mosquitto-ppa for bionic (Ubuntu 18.04 LTS). Taking a quick look shows that this appears to be due to a failure in the automated build on that platform:

https://launchpad.net/~mosquitto-dev/+archive/ubuntu/mosquitto-ppa/+packages
https://launchpad.net/~mosquitto-dev/+archive/ubuntu/mosquitto-ppa/+build/18793602

https://launchpadlibrarian.net/467539890/buildlog_ubuntu-bionic-amd64.mosquitto_1.6.9-0mosquitto1~bionic1_BUILDING.txt.gz

```
cc -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,--as-needed -Wl,--dynamic-list=linker.syms mosquitto.o alias_mosq.o bridge.o conf.o conf_includedir.o context.o database.o handle_auth.o handle_connack.o handle_connect.o handle_disconnect.o handle_ping.o handle_pubackcomp.o handle_publish.o handle_pubrec.o handle_pubrel.o handle_suback.o handle_subscribe.o handle_unsuback.o handle_unsubscribe.o logging.o loop.o memory_mosq.o misc_mosq.o net.o net_mosq.o net_mosq_ocsp.o packet_datatypes.o packet_mosq.o property_broker.o property_mosq.o persist_read.o persist_read_v234.o persist_read_v5.o persist_write.o persist_write_v5.o plugin.o read_handle.o security.o security_default.o send_auth.o send_connack.o send_connect.o send_disconnect.o send_mosq.o send_publish.o send_suback.o send_subscribe.o send_unsuback.o send_unsubscribe.o service.o session_expiry.o signals.o subs.o sys_tree.o time_mosq.o tls_mosq.o utf8_mosq.o util_mosq.o util_topic.o websockets.o will_delay.o will_mosq.o -o mosquitto  -ldl -lm -lrt -lwrap -lssl -lcrypto -lsystemd -lanl -lwebsockets 
session_expiry.o: In function `session_expiry__add':
./src/session_expiry.c:77: undefined reference to `DL_INSERT_INORDER'
will_delay.o: In function `will_delay__add':
./src/will_delay.c:48: undefined reference to `DL_INSERT_INORDER'
collect2: error: ld returned 1 exit status
Makefile:76: recipe for target 'mosquitto' failed
make[3]: *** [mosquitto] Error 1
make[3]: Leaving directory '/<<PKGBUILDDIR>>/src'
Makefile:59: recipe for target 'mosquitto' failed
make[2]: *** [mosquitto] Error 2
```

Could this be related to the 7a5c2d4da5 config.mk WITH_BUNDLED_DEPS change?
(Given that src/deps/utlist.h provides, or used to provide, the DL_INSERT_INORDER definition.)

 Comments: 
 Comment 0: Looks like the same issue for Fedora and CentOS package.

```bash
[...]
/usr/bin/ld: session_expiry.o: in function `session_expiry__add':
/home/fab/Documents/repos/packages/mosquitto/mosquitto-1.6.9/src/session_expiry.c:77: undefined reference to `DL_INSERT_INORDER'
/usr/bin/ld: will_delay.o: in function `will_delay__add':
/home/fab/Documents/repos/packages/mosquitto/mosquitto-1.6.9/src/will_delay.c:48: undefined reference to `DL_INSERT_INORDER'
collect2: error: ld returned 1 exit status
make[1]: *** [Makefile:76: mosquitto] Error 1
make[1]: Leaving directory '/home/fab/Documents/repos/packages/mosquitto/mosquitto-1.6.9/src'
make: *** [Makefile:59: mosquitto] Error 2
error: Bad exit status from /var/tmp/rpm-tmp.XHk9or (%build)
    Bad exit status from /var/tmp/rpm-tmp.XHk9or (%build)
```
 Comment 1: This was fixed a while back, so I'm closing this now.
 Comment 2: very strange, I need to install `uthash` to fix this error.
{'source': 'GithubIssues', 'repo_name_with_owner': 'eclipse/mosquitto', 'issue_id': 586683171, 'repo_stars': 6895.0}