Update decode_error_kind to decode os errors to NotSupported

library/std/src/sys/unix/mod.rs

@@ -148,6 +148,7 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
         libc::EINVAL => ErrorKind::InvalidInput,
         libc::ETIMEDOUT => ErrorKind::TimedOut,
         libc::EEXIST => ErrorKind::AlreadyExists,
+        libc::ENOSYS => ErrorKind::NotSupported,
 
         // These two constants can have the same value on some systems,
         // but different values on others, so we can't use a match

library/std/src/sys/vxworks/mod.rs

@@ -83,6 +83,7 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
         libc::EINVAL => ErrorKind::InvalidInput,
         libc::ETIMEDOUT => ErrorKind::TimedOut,
         libc::EEXIST => ErrorKind::AlreadyExists,
+        libc::ENOSYS => ErrorKind::NotSupported,
 
         // These two constants can have the same value on some systems,
         // but different values on others, so we can't use a match

library/std/src/sys/wasi/mod.rs

@@ -78,6 +78,7 @@ pub fn decode_error_kind(errno: i32) -> std_io::ErrorKind {
         wasi::ERRNO_TIMEDOUT => TimedOut,
         wasi::ERRNO_EXIST => AlreadyExists,
         wasi::ERRNO_AGAIN => WouldBlock,
+        wasi::ERRNO_NOSYS => NotSupported,
         _ => Other,
     }
 }

library/std/src/sys/windows/mod.rs

@@ -78,6 +78,7 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
         | c::ERROR_IPSEC_IKE_TIMED_OUT
         | c::ERROR_RUNLEVEL_SWITCH_TIMEOUT
         | c::ERROR_RUNLEVEL_SWITCH_AGENT_TIMEOUT => return ErrorKind::TimedOut,
+        c::ERROR_CALL_NOT_IMPLEMENTED => return ErrorKind::NotSupported,
         _ => {}
     }