Use Memcpy allocation with error handling (Follow-up to PR vgvassilev#1714) (vgvassilev#1726)

Author: leetcodez

include/clad/Differentiator/Differentiator.h

@@ -355,10 +355,11 @@ T& back(
                            "you pass clad.so to clang.");
 #endif
       size_t length = GetLength(code);
-      char* temp = (char*)malloc(length + 1);
-      m_Code = temp;
-      while ((*temp++ = *code++))
-        ;
+      m_Code = (char*)malloc(length + 1);
+      if (m_Code)
+        memcpy((void*)m_Code, code, length + 1);
+      else
+        fprintf(stderr, "Error: Failed to allocate memory for m_Code\n");
     }
 
     constexpr CUDA_HOST_DEVICE CladFunction(CladFunctionType f,