headers: crt: disable _getpid in UWP builds

It is not allowed, just like getpid.

https://docs.microsoft.com/en-us/cpp/cppcx/crt-functions-not-supported-in-universal-windows-platform-apps

Signed-off-by: Liu Hao <lh_mouse@126.com>

mingw-w64-headers/crt/process.h

diff --git a/mingw-w64-headers/crt/process.h b/mingw-w64-headers/crt/process.h
index d047568..462a902 100644
--- a/mingw-w64-headers/crt/process.h
+++ b/mingw-w64-headers/crt/process.h
@@ -63,8 +63,8 @@
 
   void __cdecl __MINGW_NOTHROW _cexit(void);
   void __cdecl __MINGW_NOTHROW _c_exit(void);
-  _CRTIMP int __cdecl _getpid(void);
 #ifdef _CRT_USE_WINAPI_FAMILY_DESKTOP_APP
+  _CRTIMP int __cdecl _getpid(void);
   _CRTIMP intptr_t __cdecl _cwait(int *_TermStat,intptr_t _ProcHandle,int _Action);
   _CRTIMP intptr_t __cdecl _execl(const char *_Filename,const char *_ArgList,...);
   _CRTIMP intptr_t __cdecl _execle(const char *_Filename,const char *_ArgList,...);