Update README.md

README.md

@@ -253,7 +253,8 @@ $ cmake ../wireshark-for-ITS
 
 - Add specific compiler options to the file epan/dissectors/CMakeFiles/dissectors.dir/flags.make:
     - Find the variable C_FLAGS
-    - Append at the end the following compiler options: " -Wno-unused-const-variable -Wno-unused-function -Wunused-const-variable"
+    - Remove the flag : "-Wunused-const-variable"
+    - Add the flag: " -Werror"
 - Build Wireshark/tshark executing the following command
 
 ```sh