headers: crt: disable _wctype global variable in winstore builds

It's not allowed (as far as 2016 doc goes):
https://docs.microsoft.com/en-us/cpp/cppcx/crt-functions-not-supported-in-universal-windows-platform-apps?view=vs-2019

"Multi-byte strings are not supported in UWP apps."

Signed-off-by: Liu Hao <lh_mouse@126.com>
diff --git a/mingw-w64-headers/crt/ctype.h b/mingw-w64-headers/crt/ctype.h
index 510772f..9b71a13 100644
--- a/mingw-w64-headers/crt/ctype.h
+++ b/mingw-w64-headers/crt/ctype.h
@@ -52,7 +52,7 @@
 #ifndef _CRT_WCTYPEDATA_DEFINED
 #define _CRT_WCTYPEDATA_DEFINED
 #ifndef _CTYPE_DISABLE_MACROS
-#ifndef _wctype
+#if !defined(_wctype) && defined(_CRT_USE_WINAPI_FAMILY_DESKTOP_APP)
 #ifdef _MSVCRT_
   extern unsigned short *_wctype;
 #else
diff --git a/mingw-w64-headers/crt/wchar.h b/mingw-w64-headers/crt/wchar.h
index 87f23ae..341e2a0 100644
--- a/mingw-w64-headers/crt/wchar.h
+++ b/mingw-w64-headers/crt/wchar.h
@@ -194,7 +194,7 @@
 #ifndef _CRT_WCTYPEDATA_DEFINED
 #define _CRT_WCTYPEDATA_DEFINED
 #ifndef _CTYPE_DISABLE_MACROS
-#ifndef _wctype
+#if !defined(_wctype) && defined(_CRT_USE_WINAPI_FAMILY_DESKTOP_APP)
 #ifdef _MSVCRT_
   extern unsigned short *_wctype;
 #else
@@ -403,7 +403,7 @@
 #define _iswprint_l(_c,_p) (_iswctype_l(_c,_BLANK|_PUNCT|_ALPHA|_DIGIT,_p))
 #define _iswgraph_l(_c,_p) (_iswctype_l(_c,_PUNCT|_ALPHA|_DIGIT,_p))
 #define _iswcntrl_l(_c,_p) (_iswctype_l(_c,_CONTROL,_p))
-#ifndef _CTYPE_DISABLE_MACROS
+#if !defined(_CTYPE_DISABLE_MACROS) && defined(_CRT_USE_WINAPI_FAMILY_DESKTOP_APP)
 #define isleadbyte(_c) (__PCTYPE_FUNC[(unsigned char)(_c)] & _LEADBYTE)
 #endif
 #endif
diff --git a/mingw-w64-headers/crt/wctype.h b/mingw-w64-headers/crt/wctype.h
index 8b1caa6..57f6ed5 100644
--- a/mingw-w64-headers/crt/wctype.h
+++ b/mingw-w64-headers/crt/wctype.h
@@ -75,7 +75,7 @@
 #ifndef _CRT_WCTYPEDATA_DEFINED
 #define _CRT_WCTYPEDATA_DEFINED
 #ifndef _CTYPE_DISABLE_MACROS
-#ifndef _wctype
+#if !defined(_wctype) && defined(_CRT_USE_WINAPI_FAMILY_DESKTOP_APP)
 #ifdef _MSVCRT_
   extern unsigned short *_wctype;
 #else