paho-mqtt fails due to C23 incompatibility of paho-mqtt-c on new compilers

[p-kraszewski]

Unfortunately, paho-mqtt is indirectly hit by C23 incompatibility of paho-mqtt-c source.

Compilation fails due to a known problem :

paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
 31 | typedef unsigned int bool;
    |                      ^~~~

paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards

Environment:

• OS Manjaro Linux
• GCC 15.1.1 20250425
• Rust stable 1.86.0 (05f9846f8 2025-03-31)
  • paho-mqtt 0.13.3
  • paho-mqtt-sys 0.10.2 (dependency)

[fpagliughi]

Yes.

There is a pull request in this repo to put in a temporary fix for us:
#249

And a discussion of the proper fix in the Paho C lib:
eclipse-paho/paho.mqtt.c#1576 (comment)

[fpagliughi]

There's a temporary fix in the -sys crate v0.10.3 from #249, and a more proper fix PR'ed to the Paho C repo in #1597 over there.

So, for now, upgrade paho-mqtt-sys to v0.10.3, and you should be good.