trying another approach

Author: devnexen

library/std/src/sys/pal/unix/thread.rs

@@ -854,32 +854,23 @@ pub mod guard {
             let guard = guardaddr
                 ..guardaddr
                     + *LOCK.get_or_init(|| {
-                        extern "C" {
-                            pub fn sysctlbyname(
-                                oid: *const libc::c_char,
-                                ov: *mut libc::c_void,
-                                osize: *mut libc::size_t,
-                                nv: *const libc::c_void,
-                                nsize: libc::size_t,
-                            ) -> libc::c_int;
-                        }
+                        use crate::sys::weak::dlsym;
+                        dlsym!(fn sysctlbyname(*const libc::c_char, *mut libc::c_void, *mut libc::size_t, *const libc::c_void, libc::size_t) -> libc::c_int);
                         let mut guard: usize = 0;
                         let mut size = crate::mem::size_of_val(&guard);
                         let oid = crate::ffi::CStr::from_bytes_with_nul(
                             b"security.bsd.stack_guard_page\0",
                         )
                         .unwrap();
-                        let res = sysctlbyname(
-                            oid.as_ptr(),
-                            &mut guard as *mut _ as *mut _,
-                            &mut size as *mut _ as *mut _,
-                            crate::ptr::null_mut(),
-                            0,
-                        );
-                        if res == 0 {
-                            return guard;
+                        match sysctlbyname.get() {
+                            Some(fcn) => {
+                                if fcn(oid.as_ptr(), &mut guard as *mut _ as *mut _, &mut size as *mut _ as *mut _, crate::ptr::null_mut(), 0) == 0 {
+                                    return guard;
+                                }
+                                return 1;
+                            },
+                            _ => { return 1; }
                         }
-                        1
                     }) * page_size;
             Some(guard)
         } else if cfg!(target_os = "openbsd") {