Add mDNS/Bonjour/Avahi (.local) support for Windows

core/net/common.odin

@@ -95,6 +95,7 @@ Resolve_Error :: enum u32 {
 }
 
 DNS_Error :: enum u32 {
+	None = 0,
 	Invalid_Hostname_Error = 1,
 	Invalid_Hosts_Config_Error,
 	Invalid_Resolv_Config_Error,
@@ -147,6 +148,8 @@ IP6_Loopback :: IP6_Address{0, 0, 0, 0, 0, 0, 0, 1}
 IP4_Any := IP4_Address{}
 IP6_Any := IP6_Address{}
 
+IP4_mDNS_Broadcast := Endpoint{address=IP4_Address{224, 0, 0, 251}, port=5353}
+
 Endpoint :: struct {
 	address: Address,
 	port:    int,

core/net/dns_windows.odin

@@ -29,9 +29,14 @@ import win "core:sys/windows"
 _get_dns_records_os :: proc(hostname: string, type: DNS_Record_Type, allocator := context.allocator) -> (records: []DNS_Record, err: DNS_Error) {
 	context.allocator = allocator
 
+	options := win.DNS_QUERY_OPTIONS{}
+	if strings.has_suffix(hostname, ".local") {
+		options = {.MULTICAST_ONLY, .MULTICAST_WAIT} // 0x00020500
+	}
+
 	host_cstr := strings.clone_to_cstring(hostname, context.temp_allocator)
 	rec: ^win.DNS_RECORD
-	res := win.DnsQuery_UTF8(host_cstr, u16(type), 0, nil, &rec, nil)
+	res := win.DnsQuery_UTF8(host_cstr, u16(type), options, nil, &rec, nil)
 
 	switch u32(res) {
 	case 0:

core/net/socket_linux.odin

@@ -35,6 +35,7 @@ Socket_Option :: enum c.int {
 	Send_Buffer_Size          = c.int(linux.Socket_Option.SNDBUF),
 	Receive_Timeout           = c.int(linux.Socket_Option.RCVTIMEO),
 	Send_Timeout              = c.int(linux.Socket_Option.SNDTIMEO),
+	Broadcast                 = c.int(linux.Socket_Option.BROADCAST),
 }
 
 // Wrappers and unwrappers for system-native types
@@ -337,7 +338,8 @@ _set_option :: proc(sock: Any_Socket, option: Socket_Option, value: any, loc :=
 		.Reuse_Address,
 		.Keep_Alive,
 		.Out_Of_Bounds_Data_Inline,
-		.TCP_Nodelay:
+		.TCP_Nodelay,
+		.Broadcast:
 		// TODO: verify whether these are options or not on Linux
 		// .Broadcast, <-- yes
 		// .Conditional_Accept,