winstorecompat: Avoid warnings about redefining _WIN32_WINNT in the Win10 library

Signed-off-by: Martin Storsjö <martin@martin.st>
diff --git a/mingw-w64-libraries/winstorecompat/src/CreateFileW.c b/mingw-w64-libraries/winstorecompat/src/CreateFileW.c
index b15378b..4771df7 100644
--- a/mingw-w64-libraries/winstorecompat/src/CreateFileW.c
+++ b/mingw-w64-libraries/winstorecompat/src/CreateFileW.c
@@ -22,7 +22,9 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x602 /* CreateFile2 is Win8 APP Family */
+#endif
 
 #define CreateFileW __CreateFileW
 #include <windef.h>
diff --git a/mingw-w64-libraries/winstorecompat/src/Crypto.c b/mingw-w64-libraries/winstorecompat/src/Crypto.c
index 8de50d4..2c3c218 100644
--- a/mingw-w64-libraries/winstorecompat/src/Crypto.c
+++ b/mingw-w64-libraries/winstorecompat/src/Crypto.c
@@ -22,7 +22,9 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x602
+#endif
 
 #define CryptAcquireContextW __CryptAcquireContextW
 #define CryptAcquireContextA __CryptAcquireContextA
diff --git a/mingw-w64-libraries/winstorecompat/src/GetFileSize.c b/mingw-w64-libraries/winstorecompat/src/GetFileSize.c
index 5f798da..8816a75 100644
--- a/mingw-w64-libraries/winstorecompat/src/GetFileSize.c
+++ b/mingw-w64-libraries/winstorecompat/src/GetFileSize.c
@@ -22,7 +22,9 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x600 /* GetFileInformationByHandleEx is Vista+ */
+#endif
 
 #define GetFileSize __GetFileSize
 #include <windef.h>
diff --git a/mingw-w64-libraries/winstorecompat/src/LoadLibraryW.c b/mingw-w64-libraries/winstorecompat/src/LoadLibraryW.c
index 9cbe216..313126f 100644
--- a/mingw-w64-libraries/winstorecompat/src/LoadLibraryW.c
+++ b/mingw-w64-libraries/winstorecompat/src/LoadLibraryW.c
@@ -22,7 +22,9 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x602 /* LoadPackagedLibrary is Win8 APP Family */
+#endif
 
 #define LoadLibraryW __LoadLibraryW
 #define LoadLibraryA __LoadLibraryA
diff --git a/mingw-w64-libraries/winstorecompat/src/UnhandledExceptionFilter.c b/mingw-w64-libraries/winstorecompat/src/UnhandledExceptionFilter.c
index 5a35183..31674b0 100644
--- a/mingw-w64-libraries/winstorecompat/src/UnhandledExceptionFilter.c
+++ b/mingw-w64-libraries/winstorecompat/src/UnhandledExceptionFilter.c
@@ -22,7 +22,9 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x501 /* UnhandledExceptionFilter is XP+ */
+#endif
 
 #define UnhandledExceptionFilter __UnhandledExceptionFilter
 #include <windef.h>
diff --git a/mingw-w64-libraries/winstorecompat/src/beginthread.c b/mingw-w64-libraries/winstorecompat/src/beginthread.c
index f96d1f7..d3f39c5 100644
--- a/mingw-w64-libraries/winstorecompat/src/beginthread.c
+++ b/mingw-w64-libraries/winstorecompat/src/beginthread.c
@@ -22,7 +22,9 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x501
+#endif
 
 #define _beginthreadex ___beginthreadex
 #define _endthreadex ___endthreadex