First of all you should test SQLite3 to see if it is already ported and working on ARM-64. If you verify that it is working, you can just check it off the list and you then qualify for the Golf shirt and the drawings for prizes.
If it does not work, you should submit a bug report to the SQLite3 bug tracking system (to let them know it isn’t working, and that you are working on a fix).
Then examine the code and see what changes you can make to the module. In the best of all worlds there is some fail-over code that you can just compile and have the module work.
If you can, test this fail-over code on other architectures such as Intel or Motorola. You could do this through QEMU as you do with ARM-64.
If the failover code does not exist, then you could try examining the existing assembly code (or codes, as there may be more than one architecture supported) and writing fail-over code to replace the assembly language code. Remember that different architectures may do different things in their assembly, so you would have to mimic this.
Finally, after testing your code, you would submit the patches to the upstream developers and have them accept them. Upon acceptance by the upstream developers, you can mark your project as “ported” and qualify for your prize(s).