Abstract get_crate_name() into macro utils.

src/macros/rustc.rs

@@ -1,11 +1,11 @@
 use proc_macro::TokenStream;
 use quote::quote;
 
+use crate::utils::get_crate_name;
+
 pub(super) fn flags_capture(args: TokenStream) -> TokenStream {
-	let cargo_crate_name = std::env::var("CARGO_CRATE_NAME");
-	let crate_name = match cargo_crate_name.as_ref() {
-		| Err(_) => return args,
-		| Ok(crate_name) => crate_name.trim_start_matches("tuwunel_"),
+	let Some(crate_name) = get_crate_name() else {
+		return args;
 	};
 
 	let flag = std::env::args().collect::<Vec<_>>();

src/macros/utils.rs

@@ -4,6 +4,18 @@ use syn::{Expr, ExprLit, Generics, Lit, Meta, MetaNameValue, parse_str};
 
 use crate::Result;
 
+pub(crate) fn get_crate_name() -> Option<String> {
+	let cargo_crate_name = std::env::var("CARGO_CRATE_NAME");
+	match cargo_crate_name.as_ref() {
+		| Err(_) => None,
+		| Ok(crate_name) => Some(
+			crate_name
+				.trim_start_matches("tuwunel_")
+				.to_owned(),
+		),
+	}
+}
+
 pub(crate) fn get_simple_settings(args: &[Meta]) -> HashMap<String, String> {
 	args.iter().fold(HashMap::new(), |mut map, arg| {
 		let Meta::NameValue(MetaNameValue { path, value, .. }) = arg else {