std: make all errors in os.zig public

lib/std/os.zig

@@ -2879,7 +2879,7 @@ pub fn bind(sock: socket_t, addr: *const sockaddr, len: socklen_t) BindError!voi
     unreachable;
 }
 
-const ListenError = error{
+pub const ListenError = error{
     /// Another socket is already listening on the same port.
     /// For Internet domain sockets, the  socket referred to by sockfd had not previously
     /// been bound to an address and, upon attempting to bind it to an ephemeral port, it
@@ -5827,7 +5827,7 @@ pub fn tcsetattr(handle: fd_t, optional_action: TCSA, termios_p: termios) Termio
     }
 }
 
-const IoCtl_SIOCGIFINDEX_Error = error{
+pub const IoCtl_SIOCGIFINDEX_Error = error{
     FileSystem,
     InterfaceNotFound,
 } || UnexpectedError;