Repository: tokio-rs/tokio
File: tokio/build.rs (Rust)

Code before:
                //
                // The oldest nightly that supports the feature is 2021-01-31.
                if ac.probe_expression(ADDR_OF_PROBE) {
                    enable_addr_of = true;
                }
            }

            // The `target_has_atomic` cfg was stabilized in 1.60.
            if ac.probe_rustc_version(1, 61) {
                enable_target_has_atomic = true;
            } else if ac.probe_rustc_version(1, 60) {
                // This compiler claims to be 1.60, but there are some nightly
                // compilers that claim to be 1.60 without supporting the
                // feature. Explicitly probe to check if code using them
                // compiles.
                //
                // The oldest nightly that supports the feature is 2022-02-11.
                if ac.probe_expression(TARGET_HAS_ATOMIC_PROBE) {
                    enable_target_has_atomic = true;
                }
            }

            // If we can't tell using `target_has_atomic`, tell if the target
            // has `AtomicU64` by trying to use it.
            if !enable_target_has_atomic && !ac.probe_expression(TARGET_ATOMIC_U64_PROBE) {
                target_needs_atomic_u64_fallback = false;
            }

            // The `Mutex::new` method was made const in 1.63.
            if ac.probe_rustc_version(1, 64) {
                enable_const_mutex_new = true;
            } else if ac.probe_rustc_version(1, 63) {
                // This compiler claims to be 1.63, but there are some nightly
                // compilers that claim to be 1.63 without supporting the
                // feature. Explicitly probe to check if code using them
                // compiles.
                //
                // The oldest nightly that supports the feature is 2022-06-20.
                if ac.probe_expression(CONST_MUTEX_NEW_PROBE) {
                    enable_const_mutex_new = true;
                }
            }
        }

        Err(e) => {
            // If we couldn't detect the compiler version and features, just
            // print a warning. This isn't a fatal error: we can still build
            // Tokio, we just can't enable cfgs automatically.
            println!(
                "cargo:warning=tokio: failed to detect compiler features: {}",
                e

Review comment (suggestion):
```suggestion
                target_needs_atomic_u64_fallback = true;
```

Code after:
                //
                // The oldest nightly that supports the feature is 2021-01-31.
                if ac.probe_expression(ADDR_OF_PROBE) {
                    enable_addr_of = true;
                }
            }

            // The `target_has_atomic` cfg was stabilized in 1.60.
            if ac.probe_rustc_version(1, 61) {
                enable_target_has_atomic = true;
            } else if ac.probe_rustc_version(1, 60) {
                // This compiler claims to be 1.60, but there are some nightly
                // compilers that claim to be 1.60 without supporting the
                // feature. Explicitly probe to check if code using them
                // compiles.
                //
                // The oldest nightly that supports the feature is 2022-02-11.
                if ac.probe_expression(TARGET_HAS_ATOMIC_PROBE) {
                    enable_target_has_atomic = true;
                }
            }

            // If we can't tell using `target_has_atomic`, tell if the target
            // has `AtomicU64` by trying to use it.
            if !enable_target_has_atomic && !ac.probe_expression(TARGET_ATOMIC_U64_PROBE) {
                target_needs_atomic_u64_fallback = true;
            }

            // The `Mutex::new` method was made const in 1.63.
            if ac.probe_rustc_version(1, 64) {
                enable_const_mutex_new = true;
            } else if ac.probe_rustc_version(1, 63) {
                // This compiler claims to be 1.63, but there are some nightly
                // compilers that claim to be 1.63 without supporting the
                // feature. Explicitly probe to check if code using them
                // compiles.
                //
                // The oldest nightly that supports the feature is 2022-06-20.
                if ac.probe_expression(CONST_MUTEX_NEW_PROBE) {
                    enable_const_mutex_new = true;
                }
            }
        }

        Err(e) => {
            // If we couldn't detect the compiler version and features, just
            // print a warning. This isn't a fatal error: we can still build
            // Tokio, we just can't enable cfgs automatically.
            println!(
                "cargo:warning=tokio: failed to detect compiler features: {}",
                e