Auto merge of #108792 - Amanieu:ohos, r=petrochenkov

Add OpenHarmony targets

- `aarch64-unknown-linux-ohos`
- `armv7-unknown-linux-ohos`

Compiler team MCP: rust-lang/compiler-team#568

std/Cargo.toml

@@ -15,7 +15,7 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core" }
-libc = { version = "0.2.139", default-features = false, features = ['rustc-dep-of-std'] }
+libc = { version = "0.2.140", default-features = false, features = ['rustc-dep-of-std'] }
 compiler_builtins = { version = "0.1.87" }
 profiler_builtins = { path = "../profiler_builtins", optional = true }
 unwind = { path = "../unwind" }

std/src/sys/unix/os.rs

@@ -115,7 +115,10 @@ 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" {
-        #[cfg_attr(any(target_os = "linux", target_env = "newlib"), link_name = "__xpg_strerror_r")]
+        #[cfg_attr(
+            all(any(target_os = "linux", target_env = "newlib"), not(target_env = "ohos")),
+            link_name = "__xpg_strerror_r"
+        )]
         fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: libc::size_t) -> c_int;
     }
 

unwind/src/lib.rs

@@ -54,6 +54,22 @@ cfg_if::cfg_if! {
     }
 }
 
+// This is the same as musl except that we default to using the system libunwind
+// instead of libgcc.
+#[cfg(target_env = "ohos")]
+cfg_if::cfg_if! {
+    if #[cfg(all(feature = "llvm-libunwind", feature = "system-llvm-libunwind"))] {
+        compile_error!("`llvm-libunwind` and `system-llvm-libunwind` cannot be enabled at the same time");
+    } else if #[cfg(feature = "llvm-libunwind")] {
+        #[link(name = "unwind", kind = "static", modifiers = "-bundle")]
+        extern "C" {}
+    } else {
+        #[link(name = "unwind", kind = "static", modifiers = "-bundle", cfg(target_feature = "crt-static"))]
+        #[link(name = "unwind", cfg(not(target_feature = "crt-static")))]
+        extern "C" {}
+    }
+}
+
 #[cfg(target_os = "android")]
 cfg_if::cfg_if! {
     if #[cfg(feature = "llvm-libunwind")] {