avr/wdt.h is part of the toolchain for the AVR architecture. If you are using a board with a microcontroller of the AVR architecture (e.g., ATmega328P on the Uno), then you will already have that library pre-installed. If you are using a board with a microcontroller of a different architecture then you can't use the library at all. So there is no use in trying to find the library.
I found this page on the "TETRIX PRIZM":
- ATmega328P processor with Arduino Optiboot bootloader installed
So I'm not sure why you would be getting this error.
Please post the full and exact text of the error output you are getting. I will provide the instructions for doing that when using the standard Arduino Web Editor. I haven't used the Chrome app so I don't know whether it will be directly applicable or not, but even if not you should be able to adapt it:
- From the menu on the left side of the Arduino Web Editor window, click "Preferences".
- Check the box next to " Always show output panel".
- Check the box next to " Console: Show verbose output".
- In the sketch pane, click the (verify) button.
- After the compilation fails, click the icon in the top right corner of the black console window at the bottom of the Arduino Web Editor window that looks like two pieces of paper.
- In a forum reply here, click on the reply field.
- Click the
</> button on the forum toolbar. This will add the forum's code block markup (
```) to your reply to make sure the compilation output is correctly formatted.
- Press Ctrl+V. This will paste the compilation output between the code tags.
- Move the cursor outside of the code tags before you add any additional text to your reply.
- Click the Reply button to post the output.