Rewrite DNS API from scratch into dedicated file(s)

From a functional point of view, the main improvement is that GetIP() now always prioritizes IPv6 over IPv4.
The previous implementation always returned an IPv4 address, unless not available: in such case it failed.
This means that now connections to hostnames should be established via IPv6 if available.

From a programmer point of view, getting rid of the insane wrappers is enough to justify a complete rewrite.

As an extra, several unrelated unused global variables are removed.

src/Cedar/Connection.c

@@ -21,6 +21,7 @@
 #include "UdpAccel.h"
 #include "Virtual.h"
 
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/Kernel.h"
 #include "Mayaqua/Mayaqua.h"
 #include "Mayaqua/Memory.h"

src/Cedar/Hub.c

@@ -19,6 +19,7 @@
 #include "Server.h"
 
 #include "Mayaqua/Cfg.h"
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/FileIO.h"
 #include "Mayaqua/Internat.h"
 #include "Mayaqua/Memory.h"

src/Cedar/Logging.c

@@ -17,6 +17,7 @@
 #include "SecureNAT.h"
 #include "Server.h"
 
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/Internat.h"
 #include "Mayaqua/FileIO.h"
 #include "Mayaqua/Memory.h"

src/Cedar/Protocol.c

@@ -30,6 +30,7 @@
 #include "Wpc.h"
 
 #include "Mayaqua/Cfg.h"
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/FileIO.h"
 #include "Mayaqua/Internat.h"
 #include "Mayaqua/Memory.h"

src/Cedar/Radius.c

@@ -11,6 +11,7 @@
 #include "IPC.h"
 #include "Server.h"
 
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/Internat.h"
 #include "Mayaqua/Memory.h"
 #include "Mayaqua/Object.h"
@@ -1717,7 +1718,7 @@ bool RadiusLogin(CONNECTION *c, char *server, UINT port, UCHAR *secret, UINT sec
 		{
 			Add(ip_list, tmp_ip);
 		}
-		else if (GetIPEx(tmp_ip, token->Token[i], true))
+		else if (GetIP(tmp_ip, token->Token[i]))
 		{
 			Add(ip_list, tmp_ip);
 		}

src/Cedar/Server.c

@@ -25,6 +25,7 @@
 #include "WinUi.h"
 
 #include "Mayaqua/Cfg.h"
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/FileIO.h"
 #include "Mayaqua/Internat.h"
 #include "Mayaqua/Memory.h"
@@ -312,8 +313,8 @@ UINT SiDebugProcGetCurrentGetIPThreadCount(SERVER *s, char *in_str, char *ret_st
 		return ERR_INVALID_PARAMETER;
 	}
 
-	ToStr3(tmp1, 0, GetCurrentGetIpThreadNum());
-	ToStr3(tmp2, 0, GetGetIpThreadMaxNum());
+	ToStr3(tmp1, 0, DnsThreadNum());
+	ToStr3(tmp2, 0, DnsThreadNumMax());
 
 	Format(ret_str, 0, 
 		"Current threads = %s\n"
@@ -5629,11 +5630,11 @@ void SiLoadServerCfg(SERVER *s, FOLDER *f)
 	i = CfgGetInt(f, "MaxConcurrentDnsClientThreads");
 	if (i != 0)
 	{
-		SetGetIpThreadMaxNum(i);
+		DnsThreadNumMaxSet(i);
 	}
 	else
 	{
-		SetGetIpThreadMaxNum(DEFAULT_GETIP_THREAD_MAX_NUM);
+		DnsThreadNumMaxSet(DNS_THREAD_DEFAULT_NUM_MAX);
 	}
 
 	s->DontBackupConfig = CfgGetBool(f, "DontBackupConfig");
@@ -6103,7 +6104,7 @@ void SiWriteServerCfg(FOLDER *f, SERVER *s)
 		return;
 	}
 
-	CfgAddInt(f, "MaxConcurrentDnsClientThreads", GetGetIpThreadMaxNum());
+	CfgAddInt(f, "MaxConcurrentDnsClientThreads", DnsThreadNumMax());
 
 	CfgAddInt(f, "CurrentBuild", s->Cedar->Build);
 
@@ -10766,7 +10767,7 @@ SERVER *SiNewServerEx(bool bridge, bool in_client_inner_server, bool relay_serve
 	LISTENER *azure;
 	LISTENER *rudp;
 
-	SetGetIpThreadMaxNum(DEFAULT_GETIP_THREAD_MAX_NUM);
+	DnsThreadNumMaxSet(DNS_THREAD_DEFAULT_NUM_MAX);
 
 	s = ZeroMalloc(sizeof(SERVER));
 

src/Cedar/UdpAccel.c

@@ -9,6 +9,7 @@
 
 #include "Connection.h"
 
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/Kernel.h"
 #include "Mayaqua/Memory.h"
 #include "Mayaqua/Object.h"

src/Cedar/Virtual.c

@@ -15,6 +15,7 @@
 #include "NativeStack.h"
 #include "Server.h"
 
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/FileIO.h"
 #include "Mayaqua/Memory.h"
 #include "Mayaqua/Object.h"

src/Cedar/Wpc.c

@@ -10,6 +10,7 @@
 #include "Command.h"
 #include "Protocol.h"
 
+#include "Mayaqua/DNS.h"
 #include "Mayaqua/Memory.h"
 #include "Mayaqua/Microsoft.h"
 #include "Mayaqua/Pack.h"