crc-fast-rust: fixed software fallback issue; swapped 2024->2021 - my own habits.

Author: loadingalias

examples/no_std_embedded/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "no_std_embedded_example"
 version = "0.1.0"
-edition = "2024"
+edition = "2021"
 publish = false
 
 [dependencies]

src/feature_detection.rs

@@ -22,9 +22,12 @@ extern crate alloc;
     any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
 ))]
 use alloc::string::{String, ToString};
-#[cfg(all(
-    feature = "std",
-    any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
+#[cfg(any(
+    test,
+    all(
+        feature = "std",
+        any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
+    )
 ))]
 use std::string::{String, ToString};
 
@@ -80,9 +83,12 @@ pub struct ArchCapabilities {
 
 /// Helper function to convert a performance tier to a human-readable target string
 /// Format: {architecture}-{intrinsics-family}-{intrinsics-features}
-#[cfg(all(
-    feature = "alloc",
-    any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
+#[cfg(any(
+    test,
+    all(
+        feature = "alloc",
+        any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
+    )
 ))]
 #[inline(always)]
 fn tier_to_target_string(tier: PerformanceTier) -> String {