rust: Enable the new_uninit feature for kernel and driver crates

The unstable new_uninit feature enables various library APIs to create
uninitialized containers, such as `Box::assume_init()`. This is
necessary to build abstractions that directly initialize memory at the
target location, instead of doing copies through the stack.

Will be used by the DRM scheduler abstraction in the kernel crate, and
by field-wise initialization (e.g. using `place!()` or a future
replacement macro which may itself live in `kernel`) in driver crates.

See [1] [2] [3] for background information.

[1] Rust-for-Linux/linux#879
[2] Rust-for-Linux/linux#2
[3] rust-lang/rust#63291

Signed-off-by: Asahi Lina <lina@asahilina.net>

rust/kernel/lib.rs

@@ -17,6 +17,7 @@
 #![feature(core_ffi_c)]
 #![feature(dispatch_from_dyn)]
 #![feature(generic_associated_types)]
+#![feature(new_uninit)]
 #![feature(receiver_trait)]
 #![feature(unsize)]
 

scripts/Makefile.build

@@ -277,7 +277,7 @@ $(obj)/%.lst: $(src)/%.c FORCE
 # Compile Rust sources (.rs)
 # ---------------------------------------------------------------------------
 
-rust_allowed_features := core_ffi_c
+rust_allowed_features := core_ffi_c,new_uninit
 
 rust_common_cmd = \
 	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \