Merge pull request #363 from dtolnay/checkcfg

Resolve unexpected_cfgs warning

build.rs

@@ -65,6 +65,16 @@ fn main() {
         None => return,
     };
 
+    if rustc >= 80 {
+        println!("cargo:rustc-check-cfg=cfg(anyhow_nightly_testing)");
+        println!("cargo:rustc-check-cfg=cfg(anyhow_no_fmt_arguments_as_str)");
+        println!("cargo:rustc-check-cfg=cfg(anyhow_no_ptr_addr_of)");
+        println!("cargo:rustc-check-cfg=cfg(anyhow_no_unsafe_op_in_unsafe_fn_lint)");
+        println!("cargo:rustc-check-cfg=cfg(doc_cfg)");
+        println!("cargo:rustc-check-cfg=cfg(error_generic_member_access)");
+        println!("cargo:rustc-check-cfg=cfg(std_backtrace)");
+    }
+
     if rustc < 51 {
         // core::ptr::addr_of
         // https://blog.rust-lang.org/2021/03/25/Rust-1.51.0.html#stabilized-apis