Auto merge of #39296 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 6 pull requests

- Successful merges: #38930, #39212, #39251, #39267, #39276, #39278
- Failed merges:

1 files changed, 8 insertions, 1 deletions

diff --git a/src/libstd/sys/redox/os.rs b/src/libstd/sys/redox/os.rs
index 135e972bca4..9d459581dd4 100644
--- a/src/libstd/sys/redox/os.rs
+++ b/src/libstd/sys/redox/os.rs
@@ -33,9 +33,16 @@ use vec;
 const TMPBUF_SZ: usize = 128;
 static ENV_LOCK: Mutex = Mutex::new();
 
+extern {
+    #[link_name = "__errno_location"]
+    fn errno_location() -> *mut i32;
+}
+
 /// Returns the platform-specific value of errno
 pub fn errno() -> i32 {
-    0
+    unsafe {
+        (*errno_location())
+    }
 }
 
 /// Gets a detailed string description for the given error number.