Fix MinGW/gcc warning about NOMINMAX being redefined

Commit 5230d62fe added a #define NOMINMAX, which conflicts with a
NOMINMAX definition in the MinGW headers. Just use the same definition
as in MinGW to fix the gcc warning.

Change-Id: Ib21dd323ebbdca5d143e394c7631303e0c72541a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/network/socket/qnativesocketengine_win.cpp

@@ -40,7 +40,7 @@
 ****************************************************************************/
 
 // Prevent windows system header files from defining min/max as macros.
-#define NOMINMAX
+#define NOMINMAX 1
 
 #include <winsock2.h>
 #include <ws2tcpip.h>

tests/auto/network/kernel/qhostinfo/tst_qhostinfo.cpp

@@ -51,7 +51,7 @@
 #endif
 
 // To prevent windows system header files from re-defining min/max
-#define NOMINMAX
+#define NOMINMAX 1
 
 #if defined(Q_OS_WIN) && !defined(QT_NO_GETADDRINFO)
 # include <winsock2.h>

tests/auto/network/socket/qtcpserver/tst_qtcpserver.cpp

@@ -41,7 +41,7 @@
 
 #include <qglobal.h>
 // To prevent windows system header files from re-defining min/max
-#define NOMINMAX
+#define NOMINMAX 1
 #if defined(_WIN32)
 #include <winsock2.h>
 #else

tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp

@@ -42,7 +42,7 @@
 #include <qglobal.h>
 
 // To prevent windows system header files from re-defining min/max
-#define NOMINMAX
+#define NOMINMAX 1
 #if defined(_WIN32)
 #include <winsock2.h>
 #else