headers: Add FlsGetValue2 in fibersapi.h

Signed-off-by: Biswapriyo Nath <nathbappai@gmail.com>
Signed-off-by: LIU Hao <lh_mouse@126.com>
diff --git a/mingw-w64-headers/include/fibersapi.h b/mingw-w64-headers/include/fibersapi.h
index 888028f..e0a1889 100644
--- a/mingw-w64-headers/include/fibersapi.h
+++ b/mingw-w64-headers/include/fibersapi.h
@@ -25,6 +25,11 @@
   WINBASEAPI WINBOOL WINAPI FlsFree (DWORD dwFlsIndex);
   WINBASEAPI WINBOOL WINAPI IsThreadAFiber (VOID);
 #endif
+
+#if (_WIN32_WINNT >= _WIN32_WINNT_WIN10)
+  WINBASEAPI PVOID WINAPI FlsGetValue2(DWORD dwTlsIndex);
+#endif
+
 #endif
 
 #ifdef __cplusplus