Remove use of `unstable` feature

Cargo.toml

@@ -26,9 +26,8 @@ rustc-std-workspace-core = { version = "1.0.0", optional = true }
 default = ["std"]
 std = []
 align = []
-rustc-dep-of-std = ['align', 'rustc-std-workspace-core', 'unstable']
+rustc-dep-of-std = ['align', 'rustc-std-workspace-core']
 extra_traits = []
-unstable = []
 # use_std is deprecated, use `std` instead
 use_std = [ 'std' ]
 

README.md

@@ -35,11 +35,6 @@ libc = "0.2"
 * `extra_traits`: all `struct`s implemented in `libc` are `Copy` and `Clone`.
   This feature derives `Debug`, `Eq`, `Hash`, and `PartialEq`.
 
-* `unstable`: This feature enables `libc` bindings that are only possible with
-  unstable Rust features. Right now, this just for
-  [`extern` `#[thread_local]` statics](https://github.com/rust-lang/rust/issues/29594)
-  on certain platforms. Requires nightly.
-
 * **deprecated**: `use_std` is deprecated, and is equivalent to `std`.
 
 ## Rust version support

build.rs

@@ -7,7 +7,6 @@ fn main() {
         rustc_minor_version().expect("Failed to get rustc version");
     let rustc_dep_of_std = env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
     let align_cargo_feature = env::var("CARGO_FEATURE_ALIGN").is_ok();
-    let unstable_cargo_feature = env::var("CARGO_FEATURE_UNSTABLE").is_ok();
 
     if env::var("CARGO_FEATURE_USE_STD").is_ok() {
         println!(
@@ -55,7 +54,7 @@ fn main() {
     }
 
     // #[thread_local] is currently unstable
-    if unstable_cargo_feature || rustc_dep_of_std {
+    if rustc_dep_of_std {
         println!("cargo:rustc-cfg=libc_thread_local");
     }
 }