Fix no_std compiles

Cargo.toml

@@ -22,7 +22,7 @@ smallvec = { version = "1.7.0", default-features = false, features = ["union", "
 thin-vec = { version = "0.2.13", default-features = false }
 ahash = { version = "0.8.2", default-features = false, features = ["compile-time-rng"] }
 num-traits = { version = "0.2.0", default-features = false }
-once_cell = { version = "1.19.0", default-features = false, features = ["critical-section"] }
+once_cell = { version = "1.20.1", default-features = false, features = ["race", "portable-atomic", "alloc"] }
 bitflags = { version = "2.0.0", default-features = false }
 smartstring = { version = "1.0.0", default-features = false }
 rhai_codegen = { version = "2.1.0", path = "codegen" }

src/config/hashing.rs

@@ -54,7 +54,11 @@ pub use crate::api::deprecated::config::hashing::{get_ahash_seed, set_ahash_seed
 /// ```
 #[inline(always)]
 pub fn set_hashing_seed(new_seed: Option<[u64; 4]>) -> Result<(), Option<[u64; 4]>> {
-    HASHING_SEED.set(new_seed)
+    #[cfg(feature = "std")]
+    return HASHING_SEED.set(new_seed);
+
+    #[cfg(not(feature = "std"))]
+    return HASHING_SEED.set(new_seed.into()).map_err(|err| *err);
 }
 
 /// Get the current hashing Seed.

src/lib.rs

@@ -220,8 +220,12 @@ type ExclusiveRange = std::ops::Range<INT>;
 /// An inclusive integer range.
 type InclusiveRange = std::ops::RangeInclusive<INT>;
 
+#[cfg(feature = "std")]
 use once_cell::sync::OnceCell;
 
+#[cfg(not(feature = "std"))]
+use once_cell::race::OnceBox as OnceCell;
+
 pub use api::build_type::{CustomType, TypeBuilder};
 #[cfg(not(feature = "no_custom_syntax"))]
 pub use api::custom_syntax::Expression;