Auto merge of #103503 - thomcc:tvos-support, r=workingjubilee

Support Apple tvOS in libstd

This target has existed in the compiler for a while, was `no_std`-only previously (even requiring `#![feature(restricted_std)]`). Apple tvOS is essentially the same as iOS, down to using the same version numbering, so there's no reason for this to be a `no_std`-only target the way it is currently.

Not yet tested much (I have an Apple TV, but haven't tested that this can deploy and run programs on it, nor the simulator). Uses the implementation strategy as the watchOS support in https://github.com/rust-lang/rust/pull/98101 and etc. That is, no `std::os::` interfaces aside from those in `std::os::unix`.

Includes an update to libc in order to pull in https://github.com/rust-lang/libc/pull/2958.

23 files changed, 180 insertions, 32 deletions

diff --git a/library/std/src/fs/tests.rs b/library/std/src/fs/tests.rs
index e2480bcbbc7..9ff01b9c35d 100644
--- a/library/std/src/fs/tests.rs
+++ b/library/std/src/fs/tests.rs
@@ -1640,6 +1640,10 @@ fn test_file_times() {
     use crate::os::ios::fs::FileTimesExt;
     #[cfg(target_os = "macos")]
     use crate::os::macos::fs::FileTimesExt;
+    #[cfg(target_os = "tvos")]
+    use crate::os::tvos::fs::FileTimesExt;
+    #[cfg(target_os = "tvos")]
+    use crate::os::tvos::fs::FileTimesExt;
     #[cfg(target_os = "watchos")]
     use crate::os::watchos::fs::FileTimesExt;
     #[cfg(windows)]
@@ -1651,9 +1655,21 @@ fn test_file_times() {
     let accessed = SystemTime::UNIX_EPOCH + Duration::from_secs(12345);
     let modified = SystemTime::UNIX_EPOCH + Duration::from_secs(54321);
     times = times.set_accessed(accessed).set_modified(modified);
-    #[cfg(any(windows, target_os = "macos", target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(
+        windows,
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "tvos",
+    ))]
     let created = SystemTime::UNIX_EPOCH + Duration::from_secs(32123);
-    #[cfg(any(windows, target_os = "macos", target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(
+        windows,
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "tvos",
+    ))]
     {
         times = times.set_created(created);
     }
@@ -1678,7 +1694,13 @@ fn test_file_times() {
     let metadata = file.metadata().unwrap();
     assert_eq!(metadata.accessed().unwrap(), accessed);
     assert_eq!(metadata.modified().unwrap(), modified);
-    #[cfg(any(windows, target_os = "macos", target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(
+        windows,
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "tvos",
+    ))]
     {
         assert_eq!(metadata.created().unwrap(), created);
     }
diff --git a/library/std/src/os/ios/fs.rs b/library/std/src/os/ios/fs.rs
index 6d4d54b7c78..b319527a541 100644
--- a/library/std/src/os/ios/fs.rs
+++ b/library/std/src/os/ios/fs.rs
@@ -6,7 +6,7 @@ use crate::sys_common::{AsInner, AsInnerMut, IntoInner};
 use crate::time::SystemTime;
 
 #[allow(deprecated)]
-use crate::os::ios::raw;
+use super::raw;
 
 /// OS-specific extensions to [`fs::Metadata`].
 ///
diff --git a/library/std/src/os/mod.rs b/library/std/src/os/mod.rs
index 5b54cc5f2e4..634c3cc4a15 100644
--- a/library/std/src/os/mod.rs
+++ b/library/std/src/os/mod.rs
@@ -137,6 +137,9 @@ pub mod redox;
 pub mod solaris;
 #[cfg(target_os = "solid_asp3")]
 pub mod solid;
+#[cfg(target_os = "tvos")]
+#[path = "ios/mod.rs"]
+pub(crate) mod tvos;
 #[cfg(target_os = "vita")]
 pub mod vita;
 #[cfg(target_os = "vxworks")]
diff --git a/library/std/src/os/unix/mod.rs b/library/std/src/os/unix/mod.rs
index 6fe1111188a..401ec1e7a01 100644
--- a/library/std/src/os/unix/mod.rs
+++ b/library/std/src/os/unix/mod.rs
@@ -73,6 +73,8 @@ mod platform {
     pub use crate::os::redox::*;
     #[cfg(target_os = "solaris")]
     pub use crate::os::solaris::*;
+    #[cfg(target_os = "tvos")]
+    pub use crate::os::tvos::*;
     #[cfg(target_os = "vita")]
     pub use crate::os::vita::*;
     #[cfg(target_os = "vxworks")]
@@ -96,6 +98,7 @@ pub mod thread;
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "watchos",
     target_os = "macos",
     target_os = "netbsd",
diff --git a/library/std/src/os/unix/net/stream.rs b/library/std/src/os/unix/net/stream.rs
index bf2a51b5edb..e20170873bb 100644
--- a/library/std/src/os/unix/net/stream.rs
+++ b/library/std/src/os/unix/net/stream.rs
@@ -11,6 +11,7 @@ use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, Owned
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "macos",
     target_os = "watchos",
     target_os = "netbsd",
@@ -30,6 +31,7 @@ use crate::time::Duration;
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "macos",
     target_os = "watchos",
     target_os = "netbsd",
@@ -238,6 +240,7 @@ impl UnixStream {
         target_os = "dragonfly",
         target_os = "freebsd",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "macos",
         target_os = "watchos",
         target_os = "netbsd",
diff --git a/library/std/src/os/unix/ucred.rs b/library/std/src/os/unix/ucred.rs
index 95967eac295..6a0cc2d2c48 100644
--- a/library/std/src/os/unix/ucred.rs
+++ b/library/std/src/os/unix/ucred.rs
@@ -36,7 +36,7 @@ pub use self::impl_linux::peer_cred;
 ))]
 pub use self::impl_bsd::peer_cred;
 
-#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
 pub use self::impl_mac::peer_cred;
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
@@ -98,7 +98,7 @@ pub mod impl_bsd {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
 pub mod impl_mac {
     use super::UCred;
     use crate::os::unix::io::AsRawFd;
diff --git a/library/std/src/os/unix/ucred/tests.rs b/library/std/src/os/unix/ucred/tests.rs
index e63a2fc248e..dd99ecdd819 100644
--- a/library/std/src/os/unix/ucred/tests.rs
+++ b/library/std/src/os/unix/ucred/tests.rs
@@ -8,6 +8,7 @@ use libc::{getegid, geteuid, getpid};
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "macos",
     target_os = "watchos",
     target_os = "openbsd"
@@ -26,7 +27,13 @@ fn test_socket_pair() {
 }
 
 #[test]
-#[cfg(any(target_os = "linux", target_os = "ios", target_os = "macos", target_os = "watchos"))]
+#[cfg(any(
+    target_os = "linux",
+    target_os = "ios",
+    target_os = "macos",
+    target_os = "watchos",
+    target_os = "tvos",
+))]
 fn test_socket_pair_pids(arg: Type) -> RetType {
     // Create two connected sockets and get their peer credentials.
     let (sock_a, sock_b) = UnixStream::pair().unwrap();
diff --git a/library/std/src/personality/gcc.rs b/library/std/src/personality/gcc.rs
index 82edb11cbd1..6552d96ca69 100644
--- a/library/std/src/personality/gcc.rs
+++ b/library/std/src/personality/gcc.rs
@@ -85,7 +85,7 @@ const UNWIND_DATA_REG: (i32, i32) = (4, 5); // a0, a1
 // https://github.com/gcc-mirror/gcc/blob/trunk/libgcc/unwind-c.c
 
 cfg_if::cfg_if! {
-    if #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(target_os = "watchos"), not(target_os = "netbsd")))] {
+    if #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(target_os = "tvos"), not(target_os = "watchos"), not(target_os = "netbsd")))] {
         // ARM EHABI personality routine.
         // https://infocenter.arm.com/help/topic/com.arm.doc.ihi0038b/IHI0038B_ehabi.pdf
         //
diff --git a/library/std/src/sys/unix/args.rs b/library/std/src/sys/unix/args.rs
index 0efe2570d67..f8fa81e6ef1 100644
--- a/library/std/src/sys/unix/args.rs
+++ b/library/std/src/sys/unix/args.rs
@@ -168,7 +168,7 @@ mod imp {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
 mod imp {
     use super::Args;
     use crate::ffi::CStr;
@@ -209,7 +209,7 @@ mod imp {
     // for i in (0..[args count])
     //      res.push([args objectAtIndex:i])
     // res
-    #[cfg(any(target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(target_os = "ios", target_os = "tvos", target_os = "watchos"))]
     pub fn args() -> Args {
         use crate::ffi::OsString;
         use crate::mem;
diff --git a/library/std/src/sys/unix/env.rs b/library/std/src/sys/unix/env.rs
index 8c3ef88d8f8..929e9dae738 100644
--- a/library/std/src/sys/unix/env.rs
+++ b/library/std/src/sys/unix/env.rs
@@ -31,6 +31,17 @@ pub mod os {
     pub const EXE_EXTENSION: &str = "";
 }
 
+#[cfg(target_os = "tvos")]
+pub mod os {
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "tvos";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".dylib";
+    pub const DLL_EXTENSION: &str = "dylib";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
+}
+
 #[cfg(target_os = "watchos")]
 pub mod os {
     pub const FAMILY: &str = "unix";
diff --git a/library/std/src/sys/unix/fd.rs b/library/std/src/sys/unix/fd.rs
index 69c93c92003..85e020ae413 100644
--- a/library/std/src/sys/unix/fd.rs
+++ b/library/std/src/sys/unix/fd.rs
@@ -44,6 +44,7 @@ const READ_LIMIT: usize = libc::ssize_t::MAX as usize;
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd",
@@ -69,6 +70,7 @@ const fn max_iov() -> usize {
     target_os = "emscripten",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "linux",
     target_os = "macos",
     target_os = "netbsd",
@@ -181,6 +183,7 @@ impl FileDesc {
         target_os = "fuchsia",
         target_os = "illumos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "linux",
         target_os = "macos",
         target_os = "netbsd",
@@ -222,6 +225,7 @@ impl FileDesc {
     #[cfg(any(
         all(target_os = "android", target_pointer_width = "32"),
         target_os = "ios",
+        target_os = "tvos",
         target_os = "macos",
     ))]
     pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
@@ -320,6 +324,7 @@ impl FileDesc {
         target_os = "fuchsia",
         target_os = "illumos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "linux",
         target_os = "macos",
         target_os = "netbsd",
@@ -361,6 +366,7 @@ impl FileDesc {
     #[cfg(any(
         all(target_os = "android", target_pointer_width = "32"),
         target_os = "ios",
+        target_os = "tvos",
         target_os = "macos",
     ))]
     pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index d2fb6238387..9cf5cfcc8d5 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -32,6 +32,7 @@ use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
     all(target_os = "linux", target_env = "gnu"),
     target_os = "macos",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "watchos",
 ))]
 use crate::sys::weak::syscall;
@@ -43,6 +44,7 @@ use libc::{c_int, mode_t};
 #[cfg(any(
     target_os = "macos",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "watchos",
     target_os = "solaris",
     all(target_os = "linux", target_env = "gnu")
@@ -360,7 +362,7 @@ pub struct FilePermissions {
 pub struct FileTimes {
     accessed: Option<SystemTime>,
     modified: Option<SystemTime>,
-    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos", target_os = "tvos"))]
     created: Option<SystemTime>,
 }
 
@@ -519,6 +521,7 @@ impl FileAttr {
         target_os = "openbsd",
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
     ))]
     pub fn created(&self) -> io::Result<SystemTime> {
@@ -530,6 +533,7 @@ impl FileAttr {
         target_os = "openbsd",
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "vita",
     )))]
@@ -611,7 +615,7 @@ impl FileTimes {
         self.modified = Some(t);
     }
 
-    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos", target_os = "tvos"))]
     pub fn set_created(&mut self, t: SystemTime) {
         self.created = Some(t);
     }
@@ -895,6 +899,7 @@ impl DirEntry {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "linux",
         target_os = "emscripten",
@@ -928,6 +933,7 @@ impl DirEntry {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "netbsd",
         target_os = "openbsd",
@@ -946,6 +952,7 @@ impl DirEntry {
     #[cfg(not(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "netbsd",
         target_os = "openbsd",
@@ -1107,11 +1114,21 @@ impl File {
         cvt_r(|| unsafe { os_fsync(self.as_raw_fd()) })?;
         return Ok(());
 
-        #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+        #[cfg(any(
+            target_os = "macos",
+            target_os = "ios",
+            target_os = "tvos",
+            target_os = "watchos",
+        ))]
         unsafe fn os_fsync(fd: c_int) -> c_int {
             libc::fcntl(fd, libc::F_FULLFSYNC)
         }
-        #[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "watchos")))]
+        #[cfg(not(any(
+            target_os = "macos",
+            target_os = "ios",
+            target_os = "tvos",
+            target_os = "watchos",
+        )))]
         unsafe fn os_fsync(fd: c_int) -> c_int {
             libc::fsync(fd)
         }
@@ -1121,7 +1138,12 @@ impl File {
         cvt_r(|| unsafe { os_datasync(self.as_raw_fd()) })?;
         return Ok(());
 
-        #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+        #[cfg(any(
+            target_os = "macos",
+            target_os = "ios",
+            target_os = "tvos",
+            target_os = "watchos",
+        ))]
         unsafe fn os_datasync(fd: c_int) -> c_int {
             libc::fcntl(fd, libc::F_FULLFSYNC)
         }
@@ -1140,6 +1162,7 @@ impl File {
             target_os = "android",
             target_os = "freebsd",
             target_os = "ios",
+            target_os = "tvos",
             target_os = "linux",
             target_os = "macos",
             target_os = "netbsd",
@@ -1249,7 +1272,7 @@ impl File {
                     io::ErrorKind::Unsupported,
                     "setting file times not supported",
                 ))
-            } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))] {
+            } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))] {
                 let mut buf = [mem::MaybeUninit::<libc::timespec>::uninit(); 3];
                 let mut num_times = 0;
                 let mut attrlist: libc::attrlist = unsafe { mem::zeroed() };
@@ -1709,6 +1732,7 @@ fn open_to_and_set_permissions(
     target_os = "android",
     target_os = "macos",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "watchos",
 )))]
 pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
@@ -1736,7 +1760,7 @@ pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
 pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
     use crate::sync::atomic::{AtomicBool, Ordering};
 
diff --git a/library/std/src/sys/unix/locks/pthread_condvar.rs b/library/std/src/sys/unix/locks/pthread_condvar.rs
index 192fa216dfa..2dc1b0c601e 100644
--- a/library/std/src/sys/unix/locks/pthread_condvar.rs
+++ b/library/std/src/sys/unix/locks/pthread_condvar.rs
@@ -32,6 +32,7 @@ impl LazyInit for AllocatedCondvar {
             if #[cfg(any(
                 target_os = "macos",
                 target_os = "ios",
+                target_os = "tvos",
                 target_os = "watchos",
                 target_os = "l4re",
                 target_os = "android",
@@ -124,6 +125,7 @@ impl Condvar {
     #[cfg(not(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "android",
         target_os = "espidf",
@@ -158,6 +160,7 @@ impl Condvar {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "android",
         target_os = "espidf",
diff --git a/library/std/src/sys/unix/mod.rs b/library/std/src/sys/unix/mod.rs
index 24566d96bcd..1b72e21a832 100644
--- a/library/std/src/sys/unix/mod.rs
+++ b/library/std/src/sys/unix/mod.rs
@@ -87,6 +87,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
             // The poll on Darwin doesn't set POLLNVAL for closed fds.
             target_os = "macos",
             target_os = "ios",
+            target_os = "tvos",
             target_os = "watchos",
             target_os = "redox",
             target_os = "l4re",
@@ -387,7 +388,7 @@ cfg_if::cfg_if! {
     } else if #[cfg(target_os = "macos")] {
         #[link(name = "System")]
         extern "C" {}
-    } else if #[cfg(any(target_os = "ios", target_os = "watchos"))] {
+    } else if #[cfg(any(target_os = "ios", target_os = "tvos", target_os = "watchos"))] {
         #[link(name = "System")]
         #[link(name = "objc")]
         #[link(name = "Security", kind = "framework")]
diff --git a/library/std/src/sys/unix/os.rs b/library/std/src/sys/unix/os.rs
index 8edfd331304..a68c14758ff 100644
--- a/library/std/src/sys/unix/os.rs
+++ b/library/std/src/sys/unix/os.rs
@@ -63,7 +63,13 @@ extern "C" {
     #[cfg_attr(any(target_os = "solaris", target_os = "illumos"), link_name = "___errno")]
     #[cfg_attr(target_os = "nto", link_name = "__get_errno_ptr")]
     #[cfg_attr(
-        any(target_os = "macos", target_os = "ios", target_os = "freebsd", target_os = "watchos"),
+        any(
+            target_os = "macos",
+            target_os = "ios",
+            target_os = "tvos",
+            target_os = "freebsd",
+            target_os = "watchos"
+        ),
         link_name = "__error"
     )]
     #[cfg_attr(target_os = "haiku", link_name = "_errnop")]
@@ -375,7 +381,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
     Ok(PathBuf::from(OsString::from_vec(e)))
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
 pub fn current_exe() -> io::Result<PathBuf> {
     unsafe {
         let mut sz: u32 = 0;
@@ -609,6 +615,7 @@ pub fn home_dir() -> Option<PathBuf> {
     #[cfg(any(
         target_os = "android",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "emscripten",
         target_os = "redox",
@@ -623,6 +630,7 @@ pub fn home_dir() -> Option<PathBuf> {
     #[cfg(not(any(
         target_os = "android",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "emscripten",
         target_os = "redox",
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index 22d9d6141f4..129e7643661 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -15,6 +15,8 @@ use crate::sys::weak::raw_syscall;
 
 #[cfg(any(
     target_os = "macos",
+    target_os = "watchos",
+    target_os = "tvos",
     target_os = "freebsd",
     all(target_os = "linux", target_env = "gnu"),
     all(target_os = "linux", target_env = "musl"),
@@ -28,7 +30,12 @@ use libc::RTP_ID as pid_t;
 #[cfg(not(target_os = "vxworks"))]
 use libc::{c_int, pid_t};
 
-#[cfg(not(any(target_os = "vxworks", target_os = "l4re")))]
+#[cfg(not(any(
+    target_os = "vxworks",
+    target_os = "l4re",
+    target_os = "tvos",
+    target_os = "watchos",
+)))]
 use libc::{gid_t, uid_t};
 
 cfg_if::cfg_if! {
@@ -84,7 +91,6 @@ impl Command {
         if let Some(ret) = self.posix_spawn(&theirs, envp.as_ref())? {
             return Ok((ret, ours));
         }
-
         let (input, output) = sys::pipe::anon_pipe()?;
 
         // Whatever happens after the fork is almost for sure going to touch or
@@ -166,9 +172,31 @@ impl Command {
         crate::sys_common::process::wait_with_output(proc, pipes)
     }
 
+    // WatchOS and TVOS headers mark the `fork`/`exec*` functions with
+    // `__WATCHOS_PROHIBITED __TVOS_PROHIBITED`, and indicate that the
+    // `posix_spawn*` functions should be used instead. It isn't entirely clear
+    // what `PROHIBITED` means here (e.g. if calls to these functions are
+    // allowed to exist in dead code), but it sounds bad, so we go out of our
+    // way to avoid that all-together.
+    #[cfg(any(target_os = "tvos", target_os = "watchos"))]
+    const ERR_APPLE_TV_WATCH_NO_FORK_EXEC: Error = io::const_io_error!(
+        ErrorKind::Unsupported,
+        "`fork`+`exec`-based process spawning is not supported on this target",
+    );
+
+    #[cfg(any(target_os = "tvos", target_os = "watchos"))]
+    unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> {
+        return Err(Self::ERR_APPLE_TV_WATCH_NO_FORK_EXEC);
+    }
+
     // Attempts to fork the process. If successful, returns Ok((0, -1))
     // in the child, and Ok((child_pid, -1)) in the parent.
-    #[cfg(not(any(target_os = "linux", all(target_os = "nto", target_env = "nto71"))))]
+    #[cfg(not(any(
+        target_os = "linux",
+        target_os = "watchos",
+        target_os = "tvos",
+        all(target_os = "nto", target_env = "nto71"),
+    )))]
     unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> {
         cvt(libc::fork()).map(|res| (res, -1))
     }
@@ -339,6 +367,7 @@ impl Command {
     // allocation). Instead we just close it manually. This will never
     // have the drop glue anyway because this code never returns (the
     // child will either exec() or invoke libc::exit)
+    #[cfg(not(any(target_os = "tvos", target_os = "watchos")))]
     unsafe fn do_exec(
         &mut self,
         stdio: ChildPipes,
@@ -445,8 +474,19 @@ impl Command {
         Err(io::Error::last_os_error())
     }
 
+    #[cfg(any(target_os = "tvos", target_os = "watchos"))]
+    unsafe fn do_exec(
+        &mut self,
+        _stdio: ChildPipes,
+        _maybe_envp: Option<&CStringArray>,
+    ) -> Result<!, io::Error> {
+        return Err(Self::ERR_APPLE_TV_WATCH_NO_FORK_EXEC);
+    }
+
     #[cfg(not(any(
         target_os = "macos",
+        target_os = "tvos",
+        target_os = "watchos",
         target_os = "freebsd",
         all(target_os = "linux", target_env = "gnu"),
         all(target_os = "linux", target_env = "musl"),
@@ -464,6 +504,9 @@ impl Command {
     // directly.
     #[cfg(any(
         target_os = "macos",
+        // FIXME: `target_os = "ios"`?
+        target_os = "tvos",
+        target_os = "watchos",
         target_os = "freebsd",
         all(target_os = "linux", target_env = "gnu"),
         all(target_os = "linux", target_env = "musl"),
@@ -550,7 +593,7 @@ impl Command {
         }
         let addchdir = match self.get_cwd() {
             Some(cwd) => {
-                if cfg!(target_os = "macos") {
+                if cfg!(any(target_os = "macos", target_os = "tvos", target_os = "watchos")) {
                     // There is a bug in macOS where a relative executable
                     // path like "../myprogram" will cause `posix_spawn` to
                     // successfully launch the program, but erroneously return
diff --git a/library/std/src/sys/unix/rand.rs b/library/std/src/sys/unix/rand.rs
index d8b63546b9e..d471be33ed5 100644
--- a/library/std/src/sys/unix/rand.rs
+++ b/library/std/src/sys/unix/rand.rs
@@ -14,6 +14,7 @@ pub fn hashmap_random_keys() -> (u64, u64) {
     unix,
     not(target_os = "macos"),
     not(target_os = "ios"),
+    not(target_os = "tvos"),
     not(target_os = "watchos"),
     not(target_os = "openbsd"),
     not(target_os = "freebsd"),
@@ -198,7 +199,7 @@ mod imp {
 // once per thread in `hashmap_random_keys`. Therefore `SecRandomCopyBytes` is
 // only used on iOS where direct access to `/dev/urandom` is blocked by the
 // sandbox.
-#[cfg(any(target_os = "ios", target_os = "watchos"))]
+#[cfg(any(target_os = "ios", target_os = "tvos", target_os = "watchos"))]
 mod imp {
     use crate::io;
     use crate::ptr;
diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index 010015667f7..893f8b8df3f 100644
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -150,7 +150,7 @@ impl Thread {
         }
     }
 
-    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
+    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
     pub fn set_name(name: &CStr) {
         unsafe {
             let name = truncate_cstr::<{ libc::MAXTHREADNAMESIZE }>(name);
@@ -283,7 +283,13 @@ impl Drop for Thread {
     }
 }
 
-#[cfg(any(target_os = "linux", target_os = "macos", target_os = "ios", target_os = "watchos"))]
+#[cfg(any(
+    target_os = "linux",
+    target_os = "macos",
+    target_os = "ios",
+    target_os = "tvos",
+    target_os = "watchos",
+))]
 fn truncate_cstr<const MAX_WITH_NUL: usize>(cstr: &CStr) -> [libc::c_char; MAX_WITH_NUL] {
     let mut result = [0; MAX_WITH_NUL];
     for (src, dst) in cstr.to_bytes().iter().zip(&mut result[..MAX_WITH_NUL - 1]) {
@@ -299,6 +305,7 @@ pub fn available_parallelism() -> io::Result<NonZeroUsize> {
             target_os = "emscripten",
             target_os = "fuchsia",
             target_os = "ios",
+            target_os = "tvos",
             target_os = "linux",
             target_os = "macos",
             target_os = "solaris",
diff --git a/library/std/src/sys/unix/thread_parking/pthread.rs b/library/std/src/sys/unix/thread_parking/pthread.rs
index 8bf4bae7a3f..ae805d84399 100644
--- a/library/std/src/sys/unix/thread_parking/pthread.rs
+++ b/library/std/src/sys/unix/thread_parking/pthread.rs
@@ -46,6 +46,7 @@ unsafe fn wait_timeout(
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "espidf",
         target_os = "horizon",
@@ -73,6 +74,7 @@ unsafe fn wait_timeout(
     #[cfg(not(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "tvos",
         target_os = "watchos",
         target_os = "espidf",
         target_os = "horizon",
@@ -120,6 +122,7 @@ impl Parker {
             if #[cfg(any(
                 target_os = "macos",
                 target_os = "ios",
+                target_os = "tvos",
                 target_os = "watchos",
                 target_os = "l4re",
                 target_os = "android",
diff --git a/library/std/src/sys/unix/time.rs b/library/std/src/sys/unix/time.rs
index a9fbc7ab108..17b4130c202 100644
--- a/library/std/src/sys/unix/time.rs
+++ b/library/std/src/sys/unix/time.rs
@@ -219,7 +219,8 @@ impl From<__timespec64> for Timespec {
 #[cfg(any(
     all(target_os = "macos", any(not(target_arch = "aarch64"))),
     target_os = "ios",
-    target_os = "watchos"
+    target_os = "watchos",
+    target_os = "tvos"
 ))]
 mod inner {
     use crate::sync::atomic::{AtomicU64, Ordering};
@@ -339,7 +340,8 @@ mod inner {
 #[cfg(not(any(
     all(target_os = "macos", any(not(target_arch = "aarch64"))),
     target_os = "ios",
-    target_os = "watchos"
+    target_os = "watchos",
+    target_os = "tvos"
 )))]
 mod inner {
     use crate::fmt;
diff --git a/library/std/src/sys/unix/weak.rs b/library/std/src/sys/unix/weak.rs
index 62ffee70bec..61088ff16ed 100644
--- a/library/std/src/sys/unix/weak.rs
+++ b/library/std/src/sys/unix/weak.rs
@@ -28,7 +28,7 @@ use crate::ptr;
 use crate::sync::atomic::{self, AtomicPtr, Ordering};
 
 // We can use true weak linkage on ELF targets.
-#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+#[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "tvos")))]
 pub(crate) macro weak {
     (fn $name:ident($($t:ty),*) -> $ret:ty) => (
         let ref $name: ExternWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
@@ -43,7 +43,7 @@ pub(crate) macro weak {
 }
 
 // On non-ELF targets, use the dlsym approximation of weak linkage.
-#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos"))]
 pub(crate) use self::dlsym as weak;
 
 pub(crate) struct ExternWeak<F: Copy> {
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index 652c695fc57..2976a9f578e 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -18,7 +18,7 @@ use crate::ffi::{c_int, c_void};
 cfg_if::cfg_if! {
     if #[cfg(any(
         target_os = "dragonfly", target_os = "freebsd",
-        target_os = "ios", target_os = "macos", target_os = "watchos",
+        target_os = "ios", target_os = "tvos", target_os = "macos", target_os = "watchos",
         target_os = "openbsd", target_os = "netbsd", target_os = "illumos",
         target_os = "solaris", target_os = "haiku", target_os = "l4re", target_os = "nto"))] {
         use crate::sys::net::netc::IPV6_JOIN_GROUP as IPV6_ADD_MEMBERSHIP;
diff --git a/library/std/src/thread/tests.rs b/library/std/src/thread/tests.rs
index b65e2572cc5..5d6b9e94ee9 100644
--- a/library/std/src/thread/tests.rs
+++ b/library/std/src/thread/tests.rs
@@ -42,6 +42,7 @@ fn test_named_thread() {
     all(target_os = "linux", target_env = "gnu"),
     target_os = "macos",
     target_os = "ios",
+    target_os = "tvos",
     target_os = "watchos"
 ))]
 #[test]