How to install extension-functions.c for sqlite3 on ubuntu

I use sqlite3 on Ubuntu and would like to add the acos and asin functions that are provided by the extension-functions.c file.

http://ift.tt/1WuSquJ

When I follow the instructions given in the source code, I get the following error and I didn't find any answer on how I could get this working. I tried on Ubuntu 15.04, 15.10 and now 16.04.

extension-functions.c: In function ‘print_elem’:
extension-functions.c:1942:10: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘int64_t {aka long int}’ [-Wformat=]
   printf("%d => %lld\n", ee,c);
          ^

Here's what I did:

• I installed sqlite3, libsqlite3-0, libsqlite3-3:i386, and libsqlite3-dev.
• I downloaded the extension-functions.c into a new folder
• inside the new folder I executed $ gcc -fPIC -lm -shared extension-functions.c -o libsqlitefunctions.so as suggested in the source code.

=> and then I get the error mentioned above.

What am I doing wong?

Thanx a lot in advance for your help.

Cheers, Dom