azure-mqtt is a general purpose library build for MQTT protocol
azure-mqtt client use the azure-c-shared-utility, which is a C library provisioning common functionality for basic tasks (like string, list manipulation, IO, etc.). azure-c-shared-utility is available here: https://github.com/Azure/azure-c-shared-utility. azure-c-shared-utility needs to be built before building azure-mqtt.