Merge pull request rust-lang#3543 from SteveLauC/socket_flags_freebsd

feat: IPV6_RECVHOPLIMIT & IP_RECVTTL for FreeBSD

Author: JohnTitor

libc-test/semver/freebsd.txt

@@ -2251,3 +2251,5 @@ closefrom
 close_range
 eventfd_read
 eventfd_write
+IP_RECVTTL
+IPV6_RECVHOPLIMIT

src/unix/bsd/freebsdlike/freebsd/mod.rs

@@ -3609,6 +3609,8 @@ pub const IP_RSS_LISTEN_BUCKET: ::c_int = 26;
 pub const IP_ORIGDSTADDR: ::c_int = 27;
 pub const IP_RECVORIGDSTADDR: ::c_int = IP_ORIGDSTADDR;
 
+pub const IP_RECVTTL: ::c_int = 65;
+pub const IPV6_RECVHOPLIMIT: ::c_int = 37;
 pub const IP_DONTFRAG: ::c_int = 67;
 pub const IP_RECVTOS: ::c_int = 68;