README's - add Mosquitto installation info

Canonical is once again pushing snaps, so the normal sudo apt-get
install will fail on Ubuntu 22.04.

README.md

@@ -12,6 +12,8 @@ Pt-example is a basic example of the C-API and pt-client usage.
 without real MQTT hardware using provided Mosquitto MQTT simulator scripts. The endpoints may
 publish for example temperature and humidity values to Device Management.
 
+NOTE! This requires Eclipse's Mosquitto - see installation info: https://mosquitto.org/download/
+
 ## blept-example
 
 The `blept-example` is a protocol translator reference implementation for use with Bluetooth Low Energy (BLE) devices that implement a Bluetooth Low Energy Generic Attributes (GATT) server. It connects to BLE devices and translates their GATT services and characteristics into Open Mobile Alliance (OMA) Lightweight Machine to Machine (LwM2M) Objects and Resources.
@@ -51,6 +53,8 @@ This example tests the robustness and thread safeness of Protocol API C-API inte
        libmosquitto-dev mosquitto-clients libglib2.0-dev \
        doxygen
     ```
+    NOTE! Mosquitto might not be available directly in your distribution (for example Ubuntu 22.04),
+    see https://mosquitto.org/download/ for more installation information.
 
 1. Preparing all the sources
 

mqttpt-example/README.md

@@ -11,6 +11,10 @@ The example translates MQTT endpoints connected to Device Management via Edge Co
 The mqttpt-example has a dependency to `jansson`-library. In the example build the
 `jansson`-library built by the `mbed-edge`-submodule is used.
 
+This example also requires Eclipse's mosquitto. 
+Mosquitto might not be available directly in your distribution (for example Ubuntu 22.04),
+see https://mosquitto.org/download/ for more installation information.
+
 ### Compilation
 
 Read the README.md in the root for the basic build instructions.

mqttpt-example/mqttgw_sim/README.md

@@ -4,10 +4,13 @@ This is an MQTT gateway simulator to test the `mqttpt-example` protocol translat
 
 ### Requirements
 Requires `mosquitto_pub` client for publishing the MQTT messages to MQTT broker.
-```
+```bash
 sudo apt install mosquitto-clients
 ```
 
+NOTE! Mosquitto might not be available directly in your distribution (for example Ubuntu 22.04),
+see https://mosquitto.org/download/ for more installation information.
+
 ### Usage
 1. Run `edge-core` and `mqttpt-example`
 2. Register MQTT gateway by running `mqtt_gw.sh` script.