Delete support for compilers without CString::into_boxed_c_str

serde/Cargo.toml

@@ -11,7 +11,7 @@ keywords = ["serde", "serialization", "no_std"]
 license = "MIT OR Apache-2.0"
 readme = "crates-io.md"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.19"
+rust-version = "1.20"
 
 [dependencies]
 serde_derive = { version = "=1.0.179", optional = true, path = "../serde_derive" }

serde/build.rs

@@ -16,11 +16,9 @@ fn main() {
     let target = env::var("TARGET").unwrap();
     let emscripten = target == "asmjs-unknown-emscripten" || target == "wasm32-unknown-emscripten";
 
-    // CString::into_boxed_c_str and PathBuf::into_boxed_path stabilized in Rust 1.20:
-    // https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str
+    // PathBuf::into_boxed_path stabilized in Rust 1.20:
     // https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.into_boxed_path
     if minor < 20 {
-        println!("cargo:rustc-cfg=no_de_boxed_c_str");
         println!("cargo:rustc-cfg=no_de_boxed_path");
     }
 

serde/src/de/impls.rs

@@ -747,10 +747,7 @@ macro_rules! forwarded_impl {
     }
 }
 
-#[cfg(all(
-    any(feature = "std", all(not(no_core_cstr), feature = "alloc")),
-    not(no_de_boxed_c_str)
-))]
+#[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
 forwarded_impl!((), Box<CStr>, CString::into_boxed_c_str);
 
 forwarded_impl!((T), Reverse<T>, Reverse);