Rollup merge of #136705 - compiler-errors:edition-library, r=jhpratt

Some miscellaneous edition-related library tweaks

Some library edition tweaks that can be done separately from upgrading the whole standard library to edition 2024 (which is blocked on getting the submodules upgraded, for example)

43 files changed, 69 insertions, 69 deletions

diff --git a/library/std/src/sys/alloc/xous.rs b/library/std/src/sys/alloc/xous.rs
index 321d30e0b11..9d22e16fdf2 100644
--- a/library/std/src/sys/alloc/xous.rs
+++ b/library/std/src/sys/alloc/xous.rs
@@ -8,7 +8,7 @@ use crate::alloc::{GlobalAlloc, Layout, System};
 static mut DLMALLOC: dlmalloc::Dlmalloc = dlmalloc::Dlmalloc::new();
 
 #[cfg(test)]
-extern "Rust" {
+unsafe extern "Rust" {
     #[link_name = "_ZN16__rust_internals3std3sys4xous5alloc8DLMALLOCE"]
     static mut DLMALLOC: dlmalloc::Dlmalloc;
 }
diff --git a/library/std/src/sys/cmath.rs b/library/std/src/sys/cmath.rs
index ee36127cfdf..e3f41f4fdbb 100644
--- a/library/std/src/sys/cmath.rs
+++ b/library/std/src/sys/cmath.rs
@@ -2,7 +2,7 @@
 
 // These symbols are all defined by `libm`,
 // or by `compiler-builtins` on unsupported platforms.
-extern "C" {
+unsafe extern "C" {
     pub fn acos(n: f64) -> f64;
     pub fn asin(n: f64) -> f64;
     pub fn atan(n: f64) -> f64;
diff --git a/library/std/src/sys/pal/hermit/mod.rs b/library/std/src/sys/pal/hermit/mod.rs
index 3d555ad5050..a746b853cbd 100644
--- a/library/std/src/sys/pal/hermit/mod.rs
+++ b/library/std/src/sys/pal/hermit/mod.rs
@@ -78,7 +78,7 @@ pub unsafe extern "C" fn runtime_entry(
     argv: *const *const c_char,
     env: *const *const c_char,
 ) -> ! {
-    extern "C" {
+    unsafe extern "C" {
         fn main(argc: isize, argv: *const *const c_char) -> i32;
     }
 
diff --git a/library/std/src/sys/pal/itron/abi.rs b/library/std/src/sys/pal/itron/abi.rs
index 5eb14bb7e53..49b5251fc0e 100644
--- a/library/std/src/sys/pal/itron/abi.rs
+++ b/library/std/src/sys/pal/itron/abi.rs
@@ -132,7 +132,7 @@ pub struct T_CTSK {
     pub stk: *mut u8,
 }
 
-extern "C" {
+unsafe extern "C" {
     #[link_name = "__asp3_acre_tsk"]
     pub fn acre_tsk(pk_ctsk: *const T_CTSK) -> ER_ID;
     #[link_name = "__asp3_get_tid"]
diff --git a/library/std/src/sys/pal/sgx/abi/mem.rs b/library/std/src/sys/pal/sgx/abi/mem.rs
index 18e6d5b3fa2..e6ce15bed3c 100644
--- a/library/std/src/sys/pal/sgx/abi/mem.rs
+++ b/library/std/src/sys/pal/sgx/abi/mem.rs
@@ -12,7 +12,7 @@ pub(crate) unsafe fn rel_ptr_mut<T>(offset: u64) -> *mut T {
     (image_base() + offset) as *mut T
 }
 
-extern "C" {
+unsafe extern "C" {
     static ENCLAVE_SIZE: usize;
     static HEAP_BASE: u64;
     static HEAP_SIZE: usize;
diff --git a/library/std/src/sys/pal/sgx/abi/mod.rs b/library/std/src/sys/pal/sgx/abi/mod.rs
index d8836452e75..f52acc41509 100644
--- a/library/std/src/sys/pal/sgx/abi/mod.rs
+++ b/library/std/src/sys/pal/sgx/abi/mod.rs
@@ -73,7 +73,7 @@ extern "C" fn entry(p1: u64, p2: u64, p3: u64, secondary: bool, p4: u64, p5: u64
 
         EntryReturn(0, 0)
     } else {
-        extern "C" {
+        unsafe extern "C" {
             fn main(argc: isize, argv: *const *const u8) -> isize;
         }
 
diff --git a/library/std/src/sys/pal/sgx/abi/panic.rs b/library/std/src/sys/pal/sgx/abi/panic.rs
index c06b97ee367..67af062b0ff 100644
--- a/library/std/src/sys/pal/sgx/abi/panic.rs
+++ b/library/std/src/sys/pal/sgx/abi/panic.rs
@@ -2,7 +2,7 @@ use super::usercalls::alloc::UserRef;
 use crate::io::{self, Write};
 use crate::{cmp, mem};
 
-extern "C" {
+unsafe extern "C" {
     fn take_debug_panic_buf_ptr() -> *mut u8;
     static DEBUG: u8;
 }
diff --git a/library/std/src/sys/pal/sgx/abi/reloc.rs b/library/std/src/sys/pal/sgx/abi/reloc.rs
index 02dff0ad29f..a4f5e4a0936 100644
--- a/library/std/src/sys/pal/sgx/abi/reloc.rs
+++ b/library/std/src/sys/pal/sgx/abi/reloc.rs
@@ -11,7 +11,7 @@ struct Rela<T> {
 }
 
 pub fn relocate_elf_rela() {
-    extern "C" {
+    unsafe extern "C" {
         static RELA: u64;
         static RELACOUNT: usize;
     }
diff --git a/library/std/src/sys/pal/sgx/abi/thread.rs b/library/std/src/sys/pal/sgx/abi/thread.rs
index 2b23e368cc3..9b37e2baf36 100644
--- a/library/std/src/sys/pal/sgx/abi/thread.rs
+++ b/library/std/src/sys/pal/sgx/abi/thread.rs
@@ -6,7 +6,7 @@ use fortanix_sgx_abi::Tcs;
 /// is a one-to-one correspondence of the ID to the address of the TCS.
 #[unstable(feature = "sgx_platform", issue = "56975")]
 pub fn current() -> Tcs {
-    extern "C" {
+    unsafe extern "C" {
         fn get_tcs_addr() -> *mut u8;
     }
     let addr = unsafe { get_tcs_addr() };
diff --git a/library/std/src/sys/pal/sgx/abi/tls/mod.rs b/library/std/src/sys/pal/sgx/abi/tls/mod.rs
index 34fc2f20d22..7131797003b 100644
--- a/library/std/src/sys/pal/sgx/abi/tls/mod.rs
+++ b/library/std/src/sys/pal/sgx/abi/tls/mod.rs
@@ -22,7 +22,7 @@ macro_rules! dup {
 #[export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_DESTRUCTORE"]
 static TLS_DESTRUCTOR: [AtomicUsize; TLS_KEYS] = dup!((* * * * * * *) (AtomicUsize::new(0)));
 
-extern "C" {
+unsafe extern "C" {
     fn get_tls_ptr() -> *const u8;
     fn set_tls_ptr(tls: *const u8);
 }
diff --git a/library/std/src/sys/pal/sgx/abi/usercalls/raw.rs b/library/std/src/sys/pal/sgx/abi/usercalls/raw.rs
index 943b771498f..28fbbc3c518 100644
--- a/library/std/src/sys/pal/sgx/abi/usercalls/raw.rs
+++ b/library/std/src/sys/pal/sgx/abi/usercalls/raw.rs
@@ -9,7 +9,7 @@ use crate::ptr::NonNull;
 #[repr(C)]
 struct UsercallReturn(u64, u64);
 
-extern "C" {
+unsafe extern "C" {
     fn usercall(nr: NonZero<u64>, p1: u64, p2: u64, abort: u64, p3: u64, p4: u64)
     -> UsercallReturn;
 }
diff --git a/library/std/src/sys/pal/solid/abi/fs.rs b/library/std/src/sys/pal/solid/abi/fs.rs
index 6864a3e7745..7f2b1f83e85 100644
--- a/library/std/src/sys/pal/solid/abi/fs.rs
+++ b/library/std/src/sys/pal/solid/abi/fs.rs
@@ -31,7 +31,7 @@ pub const DT_WHT: c_uchar = 14;
 
 pub type S_DIR = c_int;
 
-extern "C" {
+unsafe extern "C" {
     pub fn SOLID_FS_Open(fd: *mut c_int, path: *const c_char, mode: c_int) -> c_int;
     pub fn SOLID_FS_Close(fd: c_int) -> c_int;
     pub fn SOLID_FS_Read(fd: c_int, buf: *mut u8, size: usize, result: *mut usize) -> c_int;
diff --git a/library/std/src/sys/pal/solid/abi/mod.rs b/library/std/src/sys/pal/solid/abi/mod.rs
index 4d097057217..819f93f4074 100644
--- a/library/std/src/sys/pal/solid/abi/mod.rs
+++ b/library/std/src/sys/pal/solid/abi/mod.rs
@@ -33,27 +33,27 @@ pub struct SOLID_RTC_TIME {
     pub tm_wday: c_int,
 }
 
-extern "C" {
+unsafe extern "C" {
     pub fn SOLID_RTC_ReadTime(time: *mut SOLID_RTC_TIME) -> c_int;
 }
 
 // `solid_log.h`
-extern "C" {
+unsafe extern "C" {
     pub fn SOLID_LOG_write(s: *const u8, l: usize);
 }
 
 // `solid_mem.h`
-extern "C" {
+unsafe extern "C" {
     pub fn SOLID_TLS_AddDestructor(id: i32, dtor: unsafe extern "C" fn(*mut u8));
 }
 
 // `solid_rng.h`
-extern "C" {
+unsafe extern "C" {
     pub fn SOLID_RNG_SampleRandomBytes(buffer: *mut u8, length: usize) -> c_int;
 }
 
 // `rwlock.h`
-extern "C" {
+unsafe extern "C" {
     pub fn rwl_loc_rdl(id: ID) -> ER;
     pub fn rwl_loc_wrl(id: ID) -> ER;
     pub fn rwl_ploc_rdl(id: ID) -> ER;
diff --git a/library/std/src/sys/pal/solid/abi/sockets.rs b/library/std/src/sys/pal/solid/abi/sockets.rs
index 3c9e3f9ffb9..80802dd42e2 100644
--- a/library/std/src/sys/pal/solid/abi/sockets.rs
+++ b/library/std/src/sys/pal/solid/abi/sockets.rs
@@ -158,7 +158,7 @@ pub struct fd_set {
     pub fds: [c_int; SOLID_NET_FD_SETSIZE],
 }
 
-extern "C" {
+unsafe extern "C" {
     #[link_name = "SOLID_NET_StrError"]
     pub fn strerror(errnum: c_int) -> *const c_char;
 
diff --git a/library/std/src/sys/pal/solid/os.rs b/library/std/src/sys/pal/solid/os.rs
index 57c28aed3b2..e3b2e0aa50f 100644
--- a/library/std/src/sys/pal/solid/os.rs
+++ b/library/std/src/sys/pal/solid/os.rs
@@ -129,7 +129,7 @@ impl Iterator for Env {
 /// Returns a vector of (variable, value) byte-vector pairs for all the
 /// environment variables of the current process.
 pub fn env() -> Env {
-    extern "C" {
+    unsafe extern "C" {
         static mut environ: *const *const c_char;
     }
 
diff --git a/library/std/src/sys/pal/teeos/thread.rs b/library/std/src/sys/pal/teeos/thread.rs
index 15c65240ddd..c779c5f3ed8 100644
--- a/library/std/src/sys/pal/teeos/thread.rs
+++ b/library/std/src/sys/pal/teeos/thread.rs
@@ -16,7 +16,7 @@ pub struct Thread {
 unsafe impl Send for Thread {}
 unsafe impl Sync for Thread {}
 
-extern "C" {
+unsafe extern "C" {
     pub fn TEE_Wait(timeout: u32) -> u32;
 }
 
diff --git a/library/std/src/sys/pal/unix/args.rs b/library/std/src/sys/pal/unix/args.rs
index 8438a61e90f..1c87a79803c 100644
--- a/library/std/src/sys/pal/unix/args.rs
+++ b/library/std/src/sys/pal/unix/args.rs
@@ -147,7 +147,7 @@ mod imp {
     /// This allows `std::env::args` to work even in a `cdylib`, as it does on macOS and Windows.
     #[cfg(all(target_os = "linux", target_env = "gnu"))]
     #[used]
-    #[link_section = ".init_array.00099"]
+    #[unsafe(link_section = ".init_array.00099")]
     static ARGV_INIT_ARRAY: extern "C" fn(
         crate::os::raw::c_int,
         *const *const u8,
@@ -204,7 +204,7 @@ mod imp {
     }
 
     pub fn argc_argv() -> (isize, *const *const c_char) {
-        extern "C" {
+        unsafe extern "C" {
             // These functions are in crt_externs.h.
             fn _NSGetArgc() -> *mut c_int;
             fn _NSGetArgv() -> *mut *mut *mut c_char;
diff --git a/library/std/src/sys/pal/unix/futex.rs b/library/std/src/sys/pal/unix/futex.rs
index 0fc765dc87a..d4551dd6a38 100644
--- a/library/std/src/sys/pal/unix/futex.rs
+++ b/library/std/src/sys/pal/unix/futex.rs
@@ -219,7 +219,7 @@ pub fn futex_wake_all(futex: &AtomicU32) {
 }
 
 #[cfg(target_os = "emscripten")]
-extern "C" {
+unsafe extern "C" {
     fn emscripten_futex_wake(addr: *const AtomicU32, count: libc::c_int) -> libc::c_int;
     fn emscripten_futex_wait(
         addr: *const AtomicU32,
@@ -267,7 +267,7 @@ pub mod zircon {
     pub const ZX_ERR_BAD_STATE: zx_status_t = -20;
     pub const ZX_ERR_TIMED_OUT: zx_status_t = -21;
 
-    extern "C" {
+    unsafe extern "C" {
         pub fn zx_clock_get_monotonic() -> zx_time_t;
         pub fn zx_futex_wait(
             value_ptr: *const zx_futex_t,
diff --git a/library/std/src/sys/pal/unix/mod.rs b/library/std/src/sys/pal/unix/mod.rs
index 027df6c5691..c0b56d8d2b2 100644
--- a/library/std/src/sys/pal/unix/mod.rs
+++ b/library/std/src/sys/pal/unix/mod.rs
@@ -373,24 +373,24 @@ cfg_if::cfg_if! {
             cfg(target_feature = "crt-static"))]
         #[link(name = "dl", cfg(not(target_feature = "crt-static")))]
         #[link(name = "log", cfg(not(target_feature = "crt-static")))]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_os = "freebsd")] {
         #[link(name = "execinfo")]
         #[link(name = "pthread")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_os = "netbsd")] {
         #[link(name = "pthread")]
         #[link(name = "rt")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(any(target_os = "dragonfly", target_os = "openbsd"))] {
         #[link(name = "pthread")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_os = "solaris")] {
         #[link(name = "socket")]
         #[link(name = "posix4")]
         #[link(name = "pthread")]
         #[link(name = "resolv")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_os = "illumos")] {
         #[link(name = "socket")]
         #[link(name = "posix4")]
@@ -399,24 +399,24 @@ cfg_if::cfg_if! {
         #[link(name = "nsl")]
         // Use libumem for the (malloc-compatible) allocator
         #[link(name = "umem")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_vendor = "apple")] {
         // Link to `libSystem.dylib`.
         //
         // Don't get confused by the presence of `System.framework`,
         // it is a deprecated wrapper over the dynamic library.
         #[link(name = "System")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_os = "fuchsia")] {
         #[link(name = "zircon")]
         #[link(name = "fdio")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(all(target_os = "linux", target_env = "uclibc"))] {
         #[link(name = "dl")]
-        extern "C" {}
+        unsafe extern "C" {}
     } else if #[cfg(target_os = "vita")] {
         #[link(name = "pthread", kind = "static", modifiers = "-bundle")]
-        extern "C" {}
+        unsafe extern "C" {}
     }
 }
 
diff --git a/library/std/src/sys/pal/unix/os.rs b/library/std/src/sys/pal/unix/os.rs
index b83772e34c1..04199c56330 100644
--- a/library/std/src/sys/pal/unix/os.rs
+++ b/library/std/src/sys/pal/unix/os.rs
@@ -30,7 +30,7 @@ cfg_if::cfg_if! {
     }
 }
 
-extern "C" {
+unsafe extern "C" {
     #[cfg(not(any(target_os = "dragonfly", target_os = "vxworks", target_os = "rtems")))]
     #[cfg_attr(
         any(
@@ -82,7 +82,7 @@ pub fn errno() -> i32 {
 
 #[cfg(target_os = "rtems")]
 pub fn errno() -> i32 {
-    extern "C" {
+    unsafe extern "C" {
         #[thread_local]
         static _tls_errno: c_int;
     }
@@ -92,7 +92,7 @@ pub fn errno() -> i32 {
 
 #[cfg(target_os = "dragonfly")]
 pub fn errno() -> i32 {
-    extern "C" {
+    unsafe extern "C" {
         #[thread_local]
         static errno: c_int;
     }
@@ -103,7 +103,7 @@ pub fn errno() -> i32 {
 #[cfg(target_os = "dragonfly")]
 #[allow(dead_code)]
 pub fn set_errno(e: i32) {
-    extern "C" {
+    unsafe extern "C" {
         #[thread_local]
         static mut errno: c_int;
     }
@@ -115,7 +115,7 @@ pub fn set_errno(e: i32) {
 
 /// Gets a detailed string description for the given error number.
 pub fn error_string(errno: i32) -> String {
-    extern "C" {
+    unsafe extern "C" {
         #[cfg_attr(
             all(
                 any(target_os = "linux", target_os = "hurd", target_env = "newlib"),
@@ -610,7 +610,7 @@ pub unsafe fn environ() -> *mut *const *const c_char {
 // Use the `environ` static which is part of POSIX.
 #[cfg(not(target_vendor = "apple"))]
 pub unsafe fn environ() -> *mut *const *const c_char {
-    extern "C" {
+    unsafe extern "C" {
         static mut environ: *const *const c_char;
     }
     &raw mut environ
@@ -847,7 +847,7 @@ pub fn getppid() -> u32 {
 
 #[cfg(all(target_os = "linux", target_env = "gnu"))]
 pub fn glibc_version() -> Option<(usize, usize)> {
-    extern "C" {
+    unsafe extern "C" {
         fn gnu_get_libc_version() -> *const libc::c_char;
     }
     let version_cstr = unsafe { CStr::from_ptr(gnu_get_libc_version()) };
diff --git a/library/std/src/sys/pal/unix/process/zircon.rs b/library/std/src/sys/pal/unix/process/zircon.rs
index 4035e2370a3..7932bd26d76 100644
--- a/library/std/src/sys/pal/unix/process/zircon.rs
+++ b/library/std/src/sys/pal/unix/process/zircon.rs
@@ -75,7 +75,7 @@ pub struct zx_info_process_t {
     pub reserved1: u32,
 }
 
-extern "C" {
+unsafe extern "C" {
     pub fn zx_job_default() -> zx_handle_t;
 
     pub fn zx_task_kill(handle: zx_handle_t) -> zx_status_t;
@@ -115,7 +115,7 @@ pub struct fdio_spawn_action_t {
     pub reserved1: u64,
 }
 
-extern "C" {
+unsafe extern "C" {
     pub fn fdio_spawn_etc(
         job: zx_handle_t,
         flags: u32,
diff --git a/library/std/src/sys/pal/unix/thread.rs b/library/std/src/sys/pal/unix/thread.rs
index 356669980c7..479021af040 100644
--- a/library/std/src/sys/pal/unix/thread.rs
+++ b/library/std/src/sys/pal/unix/thread.rs
@@ -23,7 +23,7 @@ mod zircon {
     type zx_status_t = i32;
     pub const ZX_PROP_NAME: u32 = 3;
 
-    extern "C" {
+    unsafe extern "C" {
         pub fn zx_object_set_property(
             handle: zx_handle_t,
             property: u32,
@@ -230,7 +230,7 @@ impl Thread {
     #[cfg(target_os = "vxworks")]
     pub fn set_name(name: &CStr) {
         // FIXME(libc): adding real STATUS, ERROR type eventually.
-        extern "C" {
+        unsafe extern "C" {
             fn taskNameSet(task_id: libc::TASK_ID, task_name: *mut libc::c_char) -> libc::c_int;
         }
 
@@ -506,7 +506,7 @@ pub fn available_parallelism() -> io::Result<NonZero<usize>> {
         } else if #[cfg(target_os = "vxworks")] {
             // Note: there is also `vxCpuConfiguredGet`, closer to _SC_NPROCESSORS_CONF
             // expectations than the actual cores availability.
-            extern "C" {
+            unsafe extern "C" {
                 fn vxCpuEnabledGet() -> libc::cpuset_t;
             }
 
diff --git a/library/std/src/sys/pal/unix/thread_parking.rs b/library/std/src/sys/pal/unix/thread_parking.rs
index 72dd2031479..bef8b4fb363 100644
--- a/library/std/src/sys/pal/unix/thread_parking.rs
+++ b/library/std/src/sys/pal/unix/thread_parking.rs
@@ -8,7 +8,7 @@ use crate::ffi::{c_int, c_void};
 use crate::ptr;
 use crate::time::Duration;
 
-extern "C" {
+unsafe extern "C" {
     fn ___lwp_park60(
         clock_id: clockid_t,
         flags: c_int,
diff --git a/library/std/src/sys/pal/unix/weak.rs b/library/std/src/sys/pal/unix/weak.rs
index 35762f5a53b..5a37598f438 100644
--- a/library/std/src/sys/pal/unix/weak.rs
+++ b/library/std/src/sys/pal/unix/weak.rs
@@ -31,7 +31,7 @@ use crate::{mem, ptr};
 pub(crate) macro weak {
     (fn $name:ident($($t:ty),*) -> $ret:ty) => (
         let ref $name: ExternWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
-            extern "C" {
+            unsafe extern "C" {
                 #[linkage = "extern_weak"]
                 static $name: Option<unsafe extern "C" fn($($t),*) -> $ret>;
             }
diff --git a/library/std/src/sys/pal/wasi/fs.rs b/library/std/src/sys/pal/wasi/fs.rs
index 7779d2b97d7..7705e7f6b88 100644
--- a/library/std/src/sys/pal/wasi/fs.rs
+++ b/library/std/src/sys/pal/wasi/fs.rs
@@ -787,7 +787,7 @@ fn open_parent(p: &Path) -> io::Result<(ManuallyDrop<WasiFd>, PathBuf)> {
             }
         }
 
-        extern "C" {
+        unsafe extern "C" {
             pub fn __wasilibc_find_relpath(
                 path: *const libc::c_char,
                 abs_prefix: *mut *const libc::c_char,
diff --git a/library/std/src/sys/pal/wasi/os.rs b/library/std/src/sys/pal/wasi/os.rs
index f7701360f5a..ba2b65a1f40 100644
--- a/library/std/src/sys/pal/wasi/os.rs
+++ b/library/std/src/sys/pal/wasi/os.rs
@@ -16,7 +16,7 @@ use crate::{fmt, io, str, vec};
 mod libc {
     pub use libc::*;
 
-    extern "C" {
+    unsafe extern "C" {
         pub fn getcwd(buf: *mut c_char, size: size_t) -> *mut c_char;
         pub fn chdir(dir: *const c_char) -> c_int;
         pub fn __wasilibc_get_environ() -> *mut *mut c_char;
@@ -46,7 +46,7 @@ cfg_if::cfg_if! {
 }
 
 pub fn errno() -> i32 {
-    extern "C" {
+    unsafe extern "C" {
         #[thread_local]
         static errno: libc::c_int;
     }
diff --git a/library/std/src/sys/pal/wasi/thread.rs b/library/std/src/sys/pal/wasi/thread.rs
index f5e19f26bfe..0ae02369410 100644
--- a/library/std/src/sys/pal/wasi/thread.rs
+++ b/library/std/src/sys/pal/wasi/thread.rs
@@ -35,7 +35,7 @@ cfg_if::cfg_if! {
 
             pub const _SC_NPROCESSORS_ONLN: ffi::c_int = 84;
 
-            extern "C" {
+            unsafe extern "C" {
                 pub fn pthread_create(
                     native: *mut pthread_t,
                     attr: *const pthread_attr_t,
diff --git a/library/std/src/sys/pal/windows/c.rs b/library/std/src/sys/pal/windows/c.rs
index 9ce3e912caf..8dc61edb603 100644
--- a/library/std/src/sys/pal/windows/c.rs
+++ b/library/std/src/sys/pal/windows/c.rs
@@ -115,7 +115,7 @@ if #[cfg(not(target_vendor = "uwp"))] {
     link(name = "bcryptprimitives", kind = "raw-dylib", import_name_type = "undecorated")
 )]
 #[cfg_attr(not(target_arch = "x86"), link(name = "bcryptprimitives", kind = "raw-dylib"))]
-extern "system" {
+unsafe extern "system" {
     pub fn ProcessPrng(pbdata: *mut u8, cbdata: usize) -> BOOL;
 }
 
@@ -164,7 +164,7 @@ compat_fn_with_fallback! {
     not(target_arch = "x86"),
     link(name = "api-ms-win-core-synch-l1-2-0", kind = "raw-dylib")
 )]
-extern "system" {
+unsafe extern "system" {
     pub fn WaitOnAddress(
         address: *const c_void,
         compareaddress: *const c_void,
diff --git a/library/std/src/sys/pal/windows/compat.rs b/library/std/src/sys/pal/windows/compat.rs
index 42999da1664..2b9838437e9 100644
--- a/library/std/src/sys/pal/windows/compat.rs
+++ b/library/std/src/sys/pal/windows/compat.rs
@@ -39,7 +39,7 @@ use crate::sys::c;
 // See https://docs.microsoft.com/en-us/cpp/c-runtime-library/crt-initialization?view=msvc-170
 #[cfg(target_vendor = "win7")]
 #[used]
-#[link_section = ".CRT$XCT"]
+#[unsafe(link_section = ".CRT$XCT")]
 static INIT_TABLE_ENTRY: unsafe extern "C" fn() = init;
 
 /// Preload some imported functions.
diff --git a/library/std/src/sys/pal/windows/process/tests.rs b/library/std/src/sys/pal/windows/process/tests.rs
index 9a1eaf42fd9..90f1157d7c4 100644
--- a/library/std/src/sys/pal/windows/process/tests.rs
+++ b/library/std/src/sys/pal/windows/process/tests.rs
@@ -33,7 +33,7 @@ fn test_thread_handle() {
     assert!(p.is_ok());
     let mut p = p.unwrap();
 
-    extern "system" {
+    unsafe extern "system" {
         fn ResumeThread(_: BorrowedHandle<'_>) -> u32;
     }
     unsafe {
diff --git a/library/std/src/sys/pal/xous/os.rs b/library/std/src/sys/pal/xous/os.rs
index b0ab01a6383..307623c0425 100644
--- a/library/std/src/sys/pal/xous/os.rs
+++ b/library/std/src/sys/pal/xous/os.rs
@@ -37,7 +37,7 @@ mod eh_unwinding {
 #[cfg(not(test))]
 mod c_compat {
     use crate::os::xous::ffi::exit;
-    extern "C" {
+    unsafe extern "C" {
         fn main() -> u32;
     }
 
diff --git a/library/std/src/sys/pal/zkvm/abi.rs b/library/std/src/sys/pal/zkvm/abi.rs
index 53332d90e02..d000574f684 100644
--- a/library/std/src/sys/pal/zkvm/abi.rs
+++ b/library/std/src/sys/pal/zkvm/abi.rs
@@ -18,7 +18,7 @@ pub mod fileno {
     pub const JOURNAL: u32 = 3;
 }
 
-extern "C" {
+unsafe extern "C" {
     // Wrappers around syscalls provided by risc0-zkvm-platform:
     pub fn sys_halt();
     pub fn sys_output(output_id: u32, output_value: u32);
diff --git a/library/std/src/sys/personality/gcc.rs b/library/std/src/sys/personality/gcc.rs
index 88a25caeff0..cd2c7899f4b 100644
--- a/library/std/src/sys/personality/gcc.rs
+++ b/library/std/src/sys/personality/gcc.rs
@@ -194,7 +194,7 @@ cfg_if::cfg_if! {
                     }
                 }
                 // defined in libgcc
-                extern "C" {
+                unsafe extern "C" {
                     fn __gnu_unwind_frame(
                         exception_object: *mut uw::_Unwind_Exception,
                         context: *mut uw::_Unwind_Context,
diff --git a/library/std/src/sys/random/arc4random.rs b/library/std/src/sys/random/arc4random.rs
index 32467e9ebaa..e1957bceb90 100644
--- a/library/std/src/sys/random/arc4random.rs
+++ b/library/std/src/sys/random/arc4random.rs
@@ -25,7 +25,7 @@ use libc::arc4random_buf;
     target_os = "vita", // See https://github.com/vitasdk/newlib/blob/b89e5bc183b516945f9ee07eef483ecb916e45ff/newlib/libc/include/stdlib.h#L74
 ))]
 #[cfg_attr(target_os = "haiku", link(name = "bsd"))]
-extern "C" {
+unsafe extern "C" {
     fn arc4random_buf(buf: *mut core::ffi::c_void, nbytes: libc::size_t);
 }
 
diff --git a/library/std/src/sys/random/espidf.rs b/library/std/src/sys/random/espidf.rs
index fd52cb5559c..6f48f7f1f29 100644
--- a/library/std/src/sys/random/espidf.rs
+++ b/library/std/src/sys/random/espidf.rs
@@ -1,6 +1,6 @@
 use crate::ffi::c_void;
 
-extern "C" {
+unsafe extern "C" {
     fn esp_fill_random(buf: *mut c_void, len: usize);
 }
 
diff --git a/library/std/src/sys/random/fuchsia.rs b/library/std/src/sys/random/fuchsia.rs
index 77d72b3c5b7..269e0d9aeeb 100644
--- a/library/std/src/sys/random/fuchsia.rs
+++ b/library/std/src/sys/random/fuchsia.rs
@@ -4,7 +4,7 @@
 //! <https://fuchsia.dev/reference/syscalls/cprng_draw>.
 
 #[link(name = "zircon")]
-extern "C" {
+unsafe extern "C" {
     fn zx_cprng_draw(buffer: *mut u8, len: usize);
 }
 
diff --git a/library/std/src/sys/random/teeos.rs b/library/std/src/sys/random/teeos.rs
index fd6b24e19e9..6ca59cc12c9 100644
--- a/library/std/src/sys/random/teeos.rs
+++ b/library/std/src/sys/random/teeos.rs
@@ -1,4 +1,4 @@
-extern "C" {
+unsafe extern "C" {
     fn TEE_GenerateRandom(randomBuffer: *mut core::ffi::c_void, randomBufferLen: libc::size_t);
 }
 
diff --git a/library/std/src/sys/sync/thread_parking/darwin.rs b/library/std/src/sys/sync/thread_parking/darwin.rs
index 0553c5e19a9..a0d24a91e7c 100644
--- a/library/std/src/sys/sync/thread_parking/darwin.rs
+++ b/library/std/src/sys/sync/thread_parking/darwin.rs
@@ -24,7 +24,7 @@ const DISPATCH_TIME_NOW: dispatch_time_t = 0;
 const DISPATCH_TIME_FOREVER: dispatch_time_t = !0;
 
 // Contained in libSystem.dylib, which is linked by default.
-extern "C" {
+unsafe extern "C" {
     fn dispatch_time(when: dispatch_time_t, delta: i64) -> dispatch_time_t;
     fn dispatch_semaphore_create(val: isize) -> dispatch_semaphore_t;
     fn dispatch_semaphore_wait(dsema: dispatch_semaphore_t, timeout: dispatch_time_t) -> isize;
diff --git a/library/std/src/sys/thread_local/destructors/linux_like.rs b/library/std/src/sys/thread_local/destructors/linux_like.rs
index f473dc4d79d..817941229ee 100644
--- a/library/std/src/sys/thread_local/destructors/linux_like.rs
+++ b/library/std/src/sys/thread_local/destructors/linux_like.rs
@@ -27,7 +27,7 @@ pub unsafe fn register(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) {
     #[allow(non_camel_case_types)]
     pub struct c_int(#[allow(dead_code)] pub core::ffi::c_int);
 
-    extern "C" {
+    unsafe extern "C" {
         #[linkage = "extern_weak"]
         static __dso_handle: *mut u8;
         #[linkage = "extern_weak"]
diff --git a/library/std/src/sys/thread_local/guard/apple.rs b/library/std/src/sys/thread_local/guard/apple.rs
index fa25b116622..edcedf21e9e 100644
--- a/library/std/src/sys/thread_local/guard/apple.rs
+++ b/library/std/src/sys/thread_local/guard/apple.rs
@@ -10,7 +10,7 @@ pub fn enable() {
     #[thread_local]
     static REGISTERED: Cell<bool> = Cell::new(false);
 
-    extern "C" {
+    unsafe extern "C" {
         fn _tlv_atexit(dtor: unsafe extern "C" fn(*mut u8), arg: *mut u8);
     }
 
diff --git a/library/std/src/sys/thread_local/guard/windows.rs b/library/std/src/sys/thread_local/guard/windows.rs
index 1752b0e1208..b15a0d7c0bd 100644
--- a/library/std/src/sys/thread_local/guard/windows.rs
+++ b/library/std/src/sys/thread_local/guard/windows.rs
@@ -74,7 +74,7 @@ pub fn enable() {
     unsafe { ptr::from_ref(&CALLBACK).read_volatile() };
 }
 
-#[link_section = ".CRT$XLB"]
+#[unsafe(link_section = ".CRT$XLB")]
 #[cfg_attr(miri, used)] // Miri only considers explicitly `#[used]` statics for `lookup_link_section`
 pub static CALLBACK: unsafe extern "system" fn(*mut c_void, u32, *mut c_void) = tls_callback;
 
diff --git a/library/std/src/sys/thread_local/key/unix.rs b/library/std/src/sys/thread_local/key/unix.rs
index b4b58b34706..93bd0d1f668 100644
--- a/library/std/src/sys/thread_local/key/unix.rs
+++ b/library/std/src/sys/thread_local/key/unix.rs
@@ -8,7 +8,7 @@ mod libc {
     #[allow(non_camel_case_types)]
     pub type pthread_key_t = ffi::c_uint;
 
-    extern "C" {
+    unsafe extern "C" {
         pub fn pthread_key_create(
             key: *mut pthread_key_t,
             destructor: unsafe extern "C" fn(*mut ffi::c_void),
diff --git a/library/std/src/sys/thread_local/key/xous.rs b/library/std/src/sys/thread_local/key/xous.rs
index 2ab4bba7d8e..6c5e6447d19 100644
--- a/library/std/src/sys/thread_local/key/xous.rs
+++ b/library/std/src/sys/thread_local/key/xous.rs
@@ -59,7 +59,7 @@ static TLS_KEY_INDEX: AtomicUsize = AtomicUsize::new(1);
 static DTORS: AtomicPtr<Node> = AtomicPtr::new(ptr::null_mut());
 
 #[cfg(test)]
-extern "Rust" {
+unsafe extern "Rust" {
     #[link_name = "_ZN16__rust_internals3std3sys4xous16thread_local_key13TLS_KEY_INDEXE"]
     static TLS_KEY_INDEX: AtomicUsize;