fix(macros): added SQLX_SQLITE_REGISTER_REGEXP environment variable

[XVanilor]

Does your PR solve an issue?

Fixes #3070

As it's my first ever contribution to an open-source project, please tell me everything I've got wrong or if I can improve the PR to be clearer.

This intend to allow sqlite regexp function to be used with macros, it extends an already-supported feature.

The change also allows by-design the use of the new SQLX_SQLITE_REGISTER_REGEXP with sqlx-cli prepare command.

I'm waiting a run of CI to make sure that the new test does not fail (ie if the new SQLX_SQLITE_REGISTER_REGEXP needs to be added to the existing environment workflow).

Is this a breaking change?

No.

[abonander]

This should be added as a field in sqlx.toml instead of an environment variable:

sqlx/sqlx-core/src/config/reference.toml

Line 32 in 4893f83

[drivers.sqlite]

sqlx/sqlx-core/src/config/drivers.rs

Line 71 in 4893f83

pub struct SqliteConfig {

sqlx/sqlx-sqlite/src/options/mod.rs

Lines 642 to 674 in 4893f83

	pub(crate) fn apply_driver_config(
	mut self,
	config: &config::drivers::SqliteConfig,
	) -> crate::Result<Self> {
	#[cfg(feature = "load-extension")]
	for extension in &config.unsafe_load_extensions {
	// SAFETY: the documentation warns the user about loading extensions
	match extension {
	config::drivers::SqliteExtension::Path(path) => {
	self = unsafe { self.extension(path.clone()) }
	}
	config::drivers::SqliteExtension::PathWithEntrypoint { path, entrypoint } => {
	self =
	unsafe { self.extension_with_entrypoint(path.clone(), entrypoint.clone()) }
	}
	}
	}
	#[cfg(not(feature = "load-extension"))]
	if !config.unsafe_load_extensions.is_empty() {
	return Err(sqlx_core::Error::Configuration(
	format!(
	"sqlx.toml specifies `drivers.sqlite.unsafe-load-extensions = {:?}` \
	but extension loading is not enabled; \
	enable the `sqlite-load-extension` feature of SQLx to use SQLite extensions",
	config.unsafe_load_extensions,
	)
	.into(),
	));
	}
	Ok(self)
	}

Closing because I'm trying to pare down the backlog but please feel free to open a new PR.