Display backend for shares.

src/backend/cpu/CpuBackend.cpp

@@ -210,6 +210,24 @@ public:
 } // namespace xmrig
 
 
+const char *xmrig::backend_tag(uint32_t backend)
+{
+#   ifdef XMRIG_FEATURE_OPENCL
+    if (backend == Nonce::OPENCL) {
+        return ocl_tag();
+    }
+#   endif
+
+#   ifdef XMRIG_FEATURE_CUDA
+    if (backend == Nonce::CUDA) {
+        return cuda_tag();
+    }
+#   endif
+
+    return tag;
+}
+
+
 const char *xmrig::cpu_tag()
 {
     return tag;