Add Azure Device Update code to main

CMakeLists.txt

@@ -105,6 +105,7 @@ if (UNIT_TESTING)
   add_subdirectory(sdk/tests/core)
 
   # IoT
+  add_subdirectory(sdk/tests/iot/adu)
   add_subdirectory(sdk/tests/iot/common)
   add_subdirectory(sdk/tests/iot/hub)
   add_subdirectory(sdk/tests/iot/provisioning)

sdk/inc/azure/az_iot.h

@@ -15,6 +15,7 @@
 #ifndef _az_IOT_H
 #define _az_IOT_H
 
+#include <azure/iot/az_iot_adu_client.h>
 #include <azure/iot/az_iot_common.h>
 #include <azure/iot/az_iot_hub_client.h>
 #include <azure/iot/az_iot_hub_client_properties.h>

sdk/inc/azure/core/az_span.h

@@ -76,17 +76,24 @@ AZ_NODISCARD az_span az_span_create(uint8_t* ptr, int32_t size);
 #endif // AZ_NO_PRECONDITION_CHECKING
 
 /**
- * @brief An empty #az_span.
+ * @brief An empty #az_span literal.
  *
  * @remark There is no guarantee that the pointer backing this span will be `NULL` and the caller
  * shouldn't rely on it. However, the size will be 0.
  */
-#define AZ_SPAN_EMPTY                      \
-  (az_span)                                \
+#define AZ_SPAN_LITERAL_EMPTY              \
   {                                        \
     ._internal = {.ptr = NULL, .size = 0 } \
   }
 
+/**
+ * @brief An empty #az_span.
+ *
+ * @remark There is no guarantee that the pointer backing this span will be `NULL` and the caller
+ * shouldn't rely on it. However, the size will be 0.
+ */
+#define AZ_SPAN_EMPTY (az_span) AZ_SPAN_LITERAL_EMPTY
+
 // Returns the size (in bytes) of a literal string.
 // Note: Concatenating "" to S produces a compiler error if S is not a literal string
 //       The stored string's length does not include the \0 terminator.