Auto merge of #1248 - Ralith:flowinfo, r=gnzlbg

Expose IPV6_FLOWINFO* on Linux

Author: bors

libc-test/build.rs

@@ -701,7 +701,18 @@ fn do_ctest() {
             "AF_MAX" | "PF_MAX" => true,
 
             // These are not in a glibc release yet, only in kernel headers.
-            "AF_XDP" | "PF_XDP" | "SOL_XDP" if linux => true,
+            "AF_XDP"
+            | "PF_XDP"
+            | "SOL_XDP"
+            | "IPV6_FLOWINFO"
+            | "IPV6_FLOWLABEL_MGR"
+            | "IPV6_FLOWINFO_SEND"
+            | "IPV6_FLOWINFO_FLOWLABEL"
+            | "IPV6_FLOWINFO_PRIORITY"
+                if linux =>
+            {
+                true
+            }
 
             // Present on historical versions of iOS, but now removed in more
             // recent SDKs

src/unix/notbsd/mod.rs

@@ -785,18 +785,24 @@ pub const IP_RECVTOS: ::c_int = 13;
 pub const IP_ADD_MEMBERSHIP: ::c_int = 35;
 pub const IP_DROP_MEMBERSHIP: ::c_int = 36;
 pub const IP_TRANSPARENT: ::c_int = 19;
+pub const IPV6_FLOWINFO: ::c_int = 11;
 pub const IPV6_UNICAST_HOPS: ::c_int = 16;
 pub const IPV6_MULTICAST_IF: ::c_int = 17;
 pub const IPV6_MULTICAST_HOPS: ::c_int = 18;
 pub const IPV6_MULTICAST_LOOP: ::c_int = 19;
 pub const IPV6_ADD_MEMBERSHIP: ::c_int = 20;
 pub const IPV6_DROP_MEMBERSHIP: ::c_int = 21;
 pub const IPV6_V6ONLY: ::c_int = 26;
+pub const IPV6_FLOWLABEL_MGR: ::c_int = 32;
+pub const IPV6_FLOWINFO_SEND: ::c_int = 33;
 pub const IPV6_RECVPKTINFO: ::c_int = 49;
 pub const IPV6_PKTINFO: ::c_int = 50;
 pub const IPV6_RECVTCLASS: ::c_int = 66;
 pub const IPV6_TCLASS: ::c_int = 67;
 
+pub const IPV6_FLOWINFO_FLOWLABEL: ::c_int = 0x000fffff;
+pub const IPV6_FLOWINFO_PRIORITY: ::c_int = 0x0ff00000;
+
 pub const TCP_NODELAY: ::c_int = 1;
 pub const TCP_MAXSEG: ::c_int = 2;
 pub const TCP_CORK: ::c_int = 3;