GH-100813: Add socket.IP_PKTINFO constant (#10294)

Author: dsentinel

Doc/library/socket.rst

@@ -436,6 +436,7 @@ Constants
       ``TCP_FASTOPEN_CONNECT``, ``TCP_ULP``, ``TCP_MD5SIG_EXT``,
       ``TCP_FASTOPEN_KEY``, ``TCP_FASTOPEN_NO_COOKIE``,
       ``TCP_ZEROCOPY_RECEIVE``, ``TCP_INQ``, ``TCP_TX_DELAY``.
+      Added ``IP_PKTINFO``.
 
 .. data:: AF_CAN
           PF_CAN

Misc/NEWS.d/next/Library/2023-01-06-22-36-27.gh-issue-100813.mHRdQn.rst

@@ -0,0 +1 @@
+Add :data:`socket.IP_PKTINFO` constant.

Modules/socketmodule.c

@@ -8351,6 +8351,9 @@ PyInit__socket(void)
 #ifdef  IP_TRANSPARENT
     PyModule_AddIntMacro(m, IP_TRANSPARENT);
 #endif
+#ifdef  IP_PKTINFO
+    PyModule_AddIntMacro(m, IP_PKTINFO);
+#endif
 #ifdef IP_BIND_ADDRESS_NO_PORT
     PyModule_AddIntMacro(m, IP_BIND_ADDRESS_NO_PORT);
 #endif