Polyfill math functions for SQLite < 3.35.0

[JanJakes]

The SQLite built-in math functions are available only from version 3.35.0.

They need to be enabled during compilation using the -DSQLITE_ENABLE_MATH_FUNCTIONS flag, but luckily, both Debian and Ubuntu distros are using the flag.

However, for older SQLite versions, we may need to polyfill these functions to support them. This is only relevant when WP_SQLITE_UNSAFE_ENABLE_UNSUPPORTED_VERSIONS is used, as otherwise, the mininum supported SQLite version is 3.37.0.

See: https://sqlite.org/lang_mathfunc.html