Fix non-UNIX builds

Author: surban

library/std/src/sys/thread_local/key/sgx.rs

@@ -22,4 +22,6 @@ pub unsafe fn destroy(key: Key) {
     Tls::destroy(AbiKey::from_usize(key))
 }
 
-pub unsafe fn at_process_exit(cb: unsafe extern "C" fn()) {}
+pub unsafe fn at_process_exit(cb: unsafe extern "C" fn()) {
+    let _ = cb;
+}

library/std/src/sys/thread_local/key/windows.rs

@@ -202,5 +202,3 @@ pub unsafe fn run_dtors() {
         }
     }
 }
-
-pub unsafe fn at_process_exit(cb: unsafe extern "C" fn()) {}

library/std/src/sys/thread_local/key/xous.rs

@@ -215,5 +215,3 @@ unsafe fn run_dtors() {
 
     crate::rt::thread_cleanup();
 }
-
-pub unsafe fn at_process_exit(cb: unsafe extern "C" fn()) {}

library/std/src/sys/thread_local/mod.rs

@@ -149,7 +149,7 @@ pub(crate) mod key {
             #[cfg(test)]
             mod tests;
             mod windows;
-            pub(super) use windows::{Key, LazyKey, get, run_dtors, set, at_process_exit};
+            pub(super) use windows::{Key, LazyKey, get, run_dtors, set};
         } else if #[cfg(all(target_vendor = "fortanix", target_env = "sgx"))] {
             mod racy;
             mod sgx;
@@ -165,7 +165,7 @@ pub(crate) mod key {
             mod xous;
             pub(super) use racy::LazyKey;
             pub(crate) use xous::destroy_tls;
-            pub(super) use xous::{Key, get, set, at_process_exit};
+            pub(super) use xous::{Key, get, set};
             use xous::{create, destroy};
         }
     }