June 2024 nightly update

Replaces #571.

common/zalloc/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/common/zalloc"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = []
 edition = "2021"
-rust-version = "1.60"
+rust-version = "1.77.0"
 
 [package.metadata.docs.rs]
 all-features = true
@@ -19,8 +19,10 @@ workspace = true
 [dependencies]
 zeroize = { version = "^1.5", default-features = false }
 
+[build-dependencies]
+rustversion = { version = "1", default-features = false }
+
 [features]
 std = ["zeroize/std"]
 default = ["std"]
-# Commented for now as it requires nightly and we don't use nightly
-# allocator = []
+allocator = []

common/zalloc/build.rs

@@ -0,0 +1,10 @@
+#[rustversion::nightly]
+fn main() {
+  println!("cargo::rustc-check-cfg=cfg(zalloc_rustc_nightly)");
+  println!("cargo::rustc-cfg=zalloc_rustc_nightly");
+}
+
+#[rustversion::not(nightly)]
+fn main() {
+  println!("cargo::rustc-check-cfg=cfg(zalloc_rustc_nightly)");
+}

common/zalloc/src/lib.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
-#![cfg_attr(feature = "allocator", feature(allocator_api))]
+#![cfg_attr(all(zalloc_rustc_nightly, feature = "allocator"), feature(allocator_api))]
 
 //! Implementation of a Zeroizing Allocator, enabling zeroizing memory on deallocation.
 //! This can either be used with Box (requires nightly and the "allocator" feature) to provide the
@@ -17,12 +17,12 @@ use zeroize::Zeroize;
 /// An allocator wrapper which zeroizes its memory on dealloc.
 pub struct ZeroizingAlloc<T>(pub T);
 
-#[cfg(feature = "allocator")]
+#[cfg(all(zalloc_rustc_nightly, feature = "allocator"))]
 use core::{
   ptr::NonNull,
   alloc::{AllocError, Allocator},
 };
-#[cfg(feature = "allocator")]
+#[cfg(all(zalloc_rustc_nightly, feature = "allocator"))]
 unsafe impl<T: Allocator> Allocator for ZeroizingAlloc<T> {
   fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
     self.0.allocate(layout)