unstable: update to latest std::arch

This replaces `is_target_feature_detected!` with
`is_x86_feature_detected!` and adds the `cfg_target_feature` required
for using said macro.

Author: BurntSushi

src/lib.rs

@@ -520,7 +520,9 @@ another matching engine with fixed memory requirements.
 #![deny(missing_docs)]
 #![cfg_attr(test, deny(warnings))]
 #![cfg_attr(feature = "pattern", feature(pattern))]
-#![cfg_attr(feature = "unstable", feature(target_feature, stdsimd))]
+#![cfg_attr(
+    feature = "unstable",
+    feature(cfg_target_feature, target_feature, stdsimd))]
 
 extern crate aho_corasick;
 extern crate memchr;

src/vector/avx2.rs

@@ -8,7 +8,7 @@ pub struct AVX2VectorBuilder(());
 
 impl AVX2VectorBuilder {
     pub fn new() -> Option<AVX2VectorBuilder> {
-        if is_target_feature_detected!("avx2") {
+        if is_x86_feature_detected!("avx2") {
             Some(AVX2VectorBuilder(()))
         } else {
             None

src/vector/ssse3.rs

@@ -20,7 +20,7 @@ impl SSSE3VectorBuilder {
     /// If the SSSE3 feature is not enabled for the current target, then
     /// return `None`.
     pub fn new() -> Option<SSSE3VectorBuilder> {
-        if is_target_feature_detected!("ssse3") {
+        if is_x86_feature_detected!("ssse3") {
             Some(SSSE3VectorBuilder(()))
         } else {
             None