std: add linux support for packet sockaddr

Author: mllken

lib/std/os/linux.zig

@@ -3174,6 +3174,17 @@ pub const sockaddr = extern struct {
         path: [108]u8,
     };
 
+    /// Packet socket address
+    pub const ll = extern struct {
+        family: sa_family_t = AF.PACKET,
+        protocol: u16,
+        ifindex: i32,
+        hatype: u16,
+        pkttype: u8,
+        halen: u8,
+        addr: [8]u8,
+    };
+
     /// Netlink socket address
     pub const nl = extern struct {
         family: sa_family_t = AF.NETLINK,