Auto merge of #3320 - BrandonMFong:main, r=JohnTitor

Adding missing macros from linux/if_tun.h

Close #3151

I found the missing lines from my debian environment.
```
brandonmfong@kama:~/brando/sources/repo/rust-libc/libc-test$ lsb_release  -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 11 (bullseye)
Release:	11
Codename:	bullseye
```

Author: bors

libc-test/semver/linux.txt

@@ -895,6 +895,14 @@ IFF_MULTICAST
 IFF_MULTI_QUEUE
 IFF_NOARP
 IFF_NOFILTER
+TUN_TX_TIMESTAMP
+TUN_F_CSUM
+TUN_F_TSO4
+TUN_F_TSO6
+TUN_F_TSO_ECN
+TUN_F_UFO
+TUN_PKT_STRIP
+TUN_FLT_ALLMULTI
 IFF_NOTRAILERS
 IFF_NO_PI
 IFF_ONE_QUEUE
@@ -906,6 +914,8 @@ IFF_RUNNING
 IFF_SLAVE
 IFF_TAP
 IFF_TUN
+IFF_NAPI
+IFF_NAPI_FRAGS
 IFF_TUN_EXCL
 IFF_UP
 IFF_VNET_HDR

src/unix/linux_like/linux/mod.rs

@@ -1830,6 +1830,8 @@ pub const IFLA_INFO_SLAVE_DATA: ::c_ushort = 5;
 // linux/if_tun.h
 pub const IFF_TUN: ::c_int = 0x0001;
 pub const IFF_TAP: ::c_int = 0x0002;
+pub const IFF_NAPI: ::c_int = 0x0010;
+pub const IFF_NAPI_FRAGS: ::c_int = 0x0020;
 pub const IFF_NO_PI: ::c_int = 0x1000;
 // Read queue size
 pub const TUN_READQ_SIZE: ::c_short = 500;
@@ -1847,6 +1849,18 @@ pub const IFF_DETACH_QUEUE: ::c_int = 0x0400;
 // read-only flag
 pub const IFF_PERSIST: ::c_int = 0x0800;
 pub const IFF_NOFILTER: ::c_int = 0x1000;
+// Socket options
+pub const TUN_TX_TIMESTAMP: ::c_int = 1;
+// Features for GSO (TUNSETOFFLOAD)
+pub const TUN_F_CSUM: ::c_ushort = 0x01; /* You can hand me unchecksummed packets. */
+pub const TUN_F_TSO4: ::c_ushort = 0x02; /* I can handle TSO for IPv4 packets */
+pub const TUN_F_TSO6: ::c_ushort = 0x04; /* I can handle TSO for IPv6 packets */
+pub const TUN_F_TSO_ECN: ::c_ushort = 0x08; /* I can handle TSO with ECN bits. */
+pub const TUN_F_UFO: ::c_ushort = 0x10; /* I can handle UFO packets */
+// Protocol info prepended to the packets (when IFF_NO_PI is not set)
+pub const TUN_PKT_STRIP: ::c_int = 0x0001;
+// Accept all multicast packets
+pub const TUN_FLT_ALLMULTI: ::c_int = 0x0001;
 
 // Since Linux 3.1
 pub const SEEK_DATA: ::c_int = 3;