Make winsock.h and winsock2.h independent from the Unix headers.
Make them compatible with both the Unix C headers and the MSVCRT
headers.
Ensure compatibility with the Unix headers via the USE_WS_PREFIX
macro.
Add WINE_NOWINSOCK: prevents winsock.h from being included from
windows.h when defined.
Add ws2tcpip.h, move definitions to the right header.

diff --git a/include/ws2tcpip.h b/include/ws2tcpip.h
new file mode 100644
index 0000000..3ef49a4
--- /dev/null
+++ b/include/ws2tcpip.h
@@ -0,0 +1,57 @@
+#ifndef __WS2TCPIP__
+#define __WS2TCPIP__
+
+#ifdef USE_WS_PREFIX
+#define WS(x)    WS_##x
+#else
+#define WS(x)    x
+#endif
+
+/* FIXME: This gets defined by some Unix (Linux) header and messes things */
+#undef s6_addr
+
+typedef struct WS(in_addr6)
+{
+   u_char s6_addr[16];   /* IPv6 address */
+} IN6_ADDR, *PIN6_ADDR, *LPIN6_ADDR;
+
+typedef struct WS(sockaddr_in6)
+{
+   short   sin6_family;            /* AF_INET6 */
+   u_short sin6_port;              /* Transport level port number */
+   u_long  sin6_flowinfo;          /* IPv6 flow information */
+   struct  WS(in_addr6) sin6_addr; /* IPv6 address */
+} SOCKADDR_IN6,*PSOCKADDR_IN6, *LPSOCKADDR_IN6;
+
+typedef union sockaddr_gen
+{
+   struct WS(sockaddr) Address;
+   struct WS(sockaddr_in)  AddressIn;
+   struct WS(sockaddr_in6) AddressIn6;
+} WS(sockaddr_gen);
+
+/* Structure to keep interface specific information */
+typedef struct _INTERFACE_INFO
+{
+    u_long            iiFlags;             /* Interface flags */
+    WS(sockaddr_gen)  iiAddress;           /* Interface address */
+    WS(sockaddr_gen)  iiBroadcastAddress;  /* Broadcast address */
+    WS(sockaddr_gen)  iiNetmask;           /* Network mask */
+} INTERFACE_INFO, * LPINTERFACE_INFO;
+
+/* Possible flags for the  iiFlags - bitmask  */
+#ifndef USE_WS_PREFIX
+#define IFF_UP                0x00000001 /* Interface is up */
+#define IFF_BROADCAST         0x00000002 /* Broadcast is  supported */
+#define IFF_LOOPBACK          0x00000004 /* this is loopback interface */
+#define IFF_POINTTOPOINT      0x00000008 /* this is point-to-point interface */
+#define IFF_MULTICAST         0x00000010 /* multicast is supported */
+#else
+#define WS_IFF_UP             0x00000001 /* Interface is up */
+#define WS_IFF_BROADCAST      0x00000002 /* Broadcast is  supported */
+#define WS_IFF_LOOPBACK       0x00000004 /* this is loopback interface */
+#define WS_IFF_POINTTOPOINT   0x00000008 /* this is point-to-point interface */
+#define WS_IFF_MULTICAST      0x00000010 /* multicast is supported */
+#endif /* USE_WS_PREFIX */
+
+#endif /* __WS2TCPIP__ */