Add polyfills for ESP32S2

Author: Flole998

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Add `HistoryBuffer::as_slices()`
 - Implemented `retain` for `IndexMap` and `IndexSet`.
 - Recover `StableDeref` trait for `pool::object::Object` and `pool::boxed::Box`.
+- Add polyfills for ESP32S2
 
 ### Changed
 

Cargo.toml

@@ -34,6 +34,9 @@ atomic-polyfill = { version = "1.0.1" }
 [target.riscv32imc-unknown-none-elf.dependencies]
 atomic-polyfill = { version = "1.0.1" }
 
+[target.xtensa-esp32s2-none-elf.dependencies]
+atomic-polyfill = { version = "1.0.1" }
+
 [target.'cfg(target_arch = "avr")'.dependencies]
 atomic-polyfill = { version = "1.0.1", optional = true }
 

build.rs

@@ -76,7 +76,9 @@ fn main() -> Result<(), Box<dyn Error>> {
         println!("cargo:rustc-cfg=cas_atomic_polyfill");
     } else {
         match &target[..] {
-            "riscv32i-unknown-none-elf" | "riscv32imc-unknown-none-elf" => {
+            "riscv32i-unknown-none-elf"
+            | "riscv32imc-unknown-none-elf"
+            | "xtensa-esp32s2-none-elf" => {
                 println!("cargo:rustc-cfg=full_atomic_polyfill");
                 println!("cargo:rustc-cfg=cas_atomic_polyfill");
             }