Remove need for #[macro_use] with cfg-if

Modernizes usage of `cfg_if!` slightly

Author: alexcrichton

crates/std_detect/Cargo.toml

@@ -14,7 +14,7 @@ readme = "README.md"
 keywords = ["std", "run-time", "feature", "detection"]
 categories = ["hardware-support"]
 license = "MIT/Apache-2.0"
-edition = "2015"
+edition = "2018"
 
 [badges]
 is-it-maintained-issue-resolution = { repository = "rust-lang/stdarch" }
@@ -23,7 +23,7 @@ maintenance = { status = "experimental" }
 
 [dependencies]
 libc = { version = "0.2", optional = true, default-features = false }
-cfg-if = "0.1"
+cfg-if = "0.1.10"
 
 [dev-dependencies]
 auxv = "0.3.3"

crates/std_detect/src/detect/cache.rs

@@ -158,7 +158,7 @@ impl Cache {
         self.1.store(hi, Ordering::Relaxed);
     }
 }
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(feature = "std_detect_env_override")] {
         #[inline(never)]
         fn initialize(mut value: Initializer) {

crates/std_detect/src/detect/mod.rs

@@ -17,6 +17,8 @@
 //! due to security concerns (x86 is the big exception). These functions are
 //! implemented in the `os/{target_os}.rs` modules.
 
+use cfg_if::cfg_if;
+
 #[macro_use]
 mod error_macros;
 
@@ -132,19 +134,14 @@ pub fn features() -> impl Iterator<Item = (&'static str, bool)> {
             target_arch = "mips",
             target_arch = "mips64",
         ))] {
-            fn impl_() -> impl Iterator<Item=(&'static str, bool)> {
-                (0_u8..Feature::_last as u8).map(|discriminant: u8| {
-                    let f: Feature = unsafe { crate::mem::transmute(discriminant) };
-                    let name: &'static str = f.to_str();
-                    let enabled: bool = check_for(f);
-                    (name, enabled)
-                })
-            }
+            (0_u8..Feature::_last as u8).map(|discriminant: u8| {
+                let f: Feature = unsafe { crate::mem::transmute(discriminant) };
+                let name: &'static str = f.to_str();
+                let enabled: bool = check_for(f);
+                (name, enabled)
+            })
         } else {
-            fn impl_() -> impl Iterator<Item=(&'static str, bool)> {
-                (0_u8..0_u8).map(|_x: u8| ("", false))
-            }
+            None.into_iter()
         }
     }
-    impl_()
 }

crates/std_detect/src/detect/os/freebsd/mod.rs

@@ -2,7 +2,7 @@
 
 mod auxvec;
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(target_arch = "aarch64")] {
         mod aarch64;
         pub use self::aarch64::check_for;

crates/std_detect/src/lib.rs

@@ -20,10 +20,7 @@
 #![cfg_attr(test, allow(unused_imports))]
 #![no_std]
 
-#[macro_use]
-extern crate cfg_if;
-
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(any(feature = "std_detect_file_io", feature = "std_detect_env_override"))] {
         #[cfg_attr(test, macro_use(println))]
         extern crate std;