treewide: allow std in tests

This allows to use `dbg!` for example. Having this is beneficial in all no_std
crates. There are no disadvantages or negative implications.

uefi-raw/src/lib.rs

@@ -20,6 +20,11 @@
     unused
 )]
 
+// Useful for convenience in tests, such as `dbg!`
+#[cfg_attr(test, macro_use)]
+#[cfg(test)]
+extern crate std;
+
 #[macro_use]
 mod enums;
 

uefi/src/lib.rs

@@ -24,7 +24,7 @@
 //!
 //!     Status::SUCCESS
 //! }
-//! # extern crate std;
+//! # extern crate std; // For panic handler
 //! ```
 //!
 //! Please find more info in our [Rust UEFI Book].
@@ -235,6 +235,11 @@ extern crate self as uefi;
 #[macro_use]
 extern crate uefi_raw;
 
+// Useful for convenience in tests, such as `dbg!`
+#[cfg_attr(test, macro_use)]
+#[cfg(test)]
+extern crate std;
+
 #[macro_use]
 pub mod data_types;
 pub mod allocator;

xtask/src/check_raw.rs

@@ -354,7 +354,13 @@ fn check_item(item: &Item, src: &Path) -> Result<(), Error> {
             // Allow.
         }
         item => {
-            return Err(Error::new(ErrorKind::ForbiddenItemKind, src, item));
+            let allowed_exception = match item {
+                Item::ExternCrate(x) => x.ident == "std",
+                _ => false,
+            };
+            if !allowed_exception {
+                return Err(Error::new(ErrorKind::ForbiddenItemKind, src, item));
+            }
         }
     }