kernel-wfp: Fix/Complete some fwpuclnt functionality in MinGW

While MinGW declares all the required symbols, some of them are missing in the
library files. We provide missing variables locally, functions get a stub
that call the GetProcAddress()ed function from the DLL.

Also some MinGW headers define some enum values incorrectly, we overload these
using defines.

src/libcharon/plugins/kernel_wfp/kernel_wfp_compat.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2013 Martin Willi
+ * Copyright (C) 2013 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup kernel_wfp_compat kernel_wfp_compat
+ * @{ @ingroup kernel_wfp
+ */
+
+#ifndef KERNEL_WFP_COMPAT_H_
+#define KERNEL_WFP_COMPAT_H_
+
+#include <winsock2.h>
+#include <windows.h>
+#include <ipsectypes.h>
+
+/* MinGW defines CIPHERs incorrectly starting at 0 */
+#define IPSEC_CIPHER_TYPE_DES					1
+#define IPSEC_CIPHER_TYPE_3DES					2
+#define IPSEC_CIPHER_TYPE_AES_128				3
+#define IPSEC_CIPHER_TYPE_AES_192				4
+#define IPSEC_CIPHER_TYPE_AES_256				5
+#define IPSEC_CIPHER_TYPE_MAX					6
+
+#include <fwpmtypes.h>
+#include <fwpmu.h>
+#undef interface
+
+/* MinGW defines TRANSFORMs incorrectly starting at 0 */
+#define IPSEC_TRANSFORM_AH						1
+#define IPSEC_TRANSFORM_ESP_AUTH				2
+#define IPSEC_TRANSFORM_ESP_CIPHER				3
+#define IPSEC_TRANSFORM_ESP_AUTH_AND_CIPHER		4
+#define IPSEC_TRANSFORM_ESP_AUTH_FW				5
+#define IPSEC_TRANSFORM_TYPE_MAX				6
+
+#endif /** KERNEL_WFP_COMPAT_H_ @}*/