I would like to compile the extension [extension-functions.c](https://www.sqlite.org/contrib). I downloaded this file & tried to compile with Visual Studio: sqlite3ext.h was missing. I downloaded this file & added it to the project. I am getting this error: ><b>Severity</b>|<b>Code</b>|<b>Description</b> >Error|LNK1561|entry point must be defined 1. How do I overcome this? 2. How can I include the source code into [the 3.34.0 amalgamation](https://www.sqlite.org/2020/sqlite-amalgamation-3340000.zip) so that I have the extension incorporated?