std.os.windows: restore sendmsg, sendto, recvfrom

These regressed with 1a99888

I'm not ready to tackle std.posix quite yet

Author: andrewrk

lib/std/os/windows.zig

@@ -1690,6 +1690,40 @@ pub fn getpeername(s: ws2_32.SOCKET, name: *ws2_32.sockaddr, namelen: *ws2_32.so
     return ws2_32.getpeername(s, name, @as(*i32, @ptrCast(namelen)));
 }
 
+pub fn sendmsg(
+    s: ws2_32.SOCKET,
+    msg: *ws2_32.WSAMSG_const,
+    flags: u32,
+) i32 {
+    var bytes_send: DWORD = undefined;
+    if (ws2_32.WSASendMsg(s, msg, flags, &bytes_send, null, null) == ws2_32.SOCKET_ERROR) {
+        return ws2_32.SOCKET_ERROR;
+    } else {
+        return @as(i32, @as(u31, @intCast(bytes_send)));
+    }
+}
+
+pub fn sendto(s: ws2_32.SOCKET, buf: [*]const u8, len: usize, flags: u32, to: ?*const ws2_32.sockaddr, to_len: ws2_32.socklen_t) i32 {
+    var buffer = ws2_32.WSABUF{ .len = @as(u31, @truncate(len)), .buf = @constCast(buf) };
+    var bytes_send: DWORD = undefined;
+    if (ws2_32.WSASendTo(s, @as([*]ws2_32.WSABUF, @ptrCast(&buffer)), 1, &bytes_send, flags, to, @as(i32, @intCast(to_len)), null, null) == ws2_32.SOCKET_ERROR) {
+        return ws2_32.SOCKET_ERROR;
+    } else {
+        return @as(i32, @as(u31, @intCast(bytes_send)));
+    }
+}
+
+pub fn recvfrom(s: ws2_32.SOCKET, buf: [*]u8, len: usize, flags: u32, from: ?*ws2_32.sockaddr, from_len: ?*ws2_32.socklen_t) i32 {
+    var buffer = ws2_32.WSABUF{ .len = @as(u31, @truncate(len)), .buf = buf };
+    var bytes_received: DWORD = undefined;
+    var flags_inout = flags;
+    if (ws2_32.WSARecvFrom(s, @as([*]ws2_32.WSABUF, @ptrCast(&buffer)), 1, &bytes_received, &flags_inout, from, @as(?*i32, @ptrCast(from_len)), null, null) == ws2_32.SOCKET_ERROR) {
+        return ws2_32.SOCKET_ERROR;
+    } else {
+        return @as(i32, @as(u31, @intCast(bytes_received)));
+    }
+}
+
 pub fn poll(fds: [*]ws2_32.pollfd, n: c_ulong, timeout: i32) i32 {
     return ws2_32.WSAPoll(fds, n, timeout);
 }