kernel32: Add a stub for CancelSynchronousIo.

dlls/api-ms-win-core-io-l1-1-1/api-ms-win-core-io-l1-1-1.spec

 @ stdcall CancelIo(long) kernel32.CancelIo
 @ stdcall CancelIoEx(long ptr) kernel32.CancelIoEx
-@ stub CancelSynchronousIo
+@ stdcall CancelSynchronousIo(long) kernel32.CancelSynchronousIo
 @ stdcall CreateIoCompletionPort(long long long long) kernel32.CreateIoCompletionPort
 @ stdcall DeviceIoControl(long long ptr long ptr long ptr ptr) kernel32.DeviceIoControl
 @ stdcall GetOverlappedResult(long ptr ptr long) kernel32.GetOverlappedResult

dlls/kernel32/file.c

@@ -686,6 +686,25 @@ BOOL WINAPI CancelIo(HANDLE handle)
 }
 
 /***********************************************************************
+ *             CancelSynchronousIo                   (KERNEL32.@)
+ *
+ * Marks pending synchronous I/O operations issued by the specified thread as cancelled
+ *
+ * PARAMS
+ *  handle [I] handle to the thread whose I/O operations should be cancelled
+ *
+ * RETURNS
+ *  Success: TRUE.
+ *  Failure: FALSE, check GetLastError().
+ */
+BOOL WINAPI CancelSynchronousIo(HANDLE thread)
+{
+    FIXME("(%p): stub\n", thread);
+    SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
+    return FALSE;
+}
+
+/***********************************************************************
  *           _hread   (KERNEL32.@)
  */
 LONG WINAPI _hread( HFILE hFile, LPVOID buffer, LONG count)

dlls/kernel32/kernel32.spec

@@ -210,7 +210,7 @@
 @ stub CancelDeviceWakeupRequest
 @ stdcall CancelIo(long)
 @ stdcall CancelIoEx(long ptr)
-# @ stub CancelSynchronousIo
+@ stdcall CancelSynchronousIo(long)
 # @ stub CancelThreadpoolIo
 @ stdcall CancelTimerQueueTimer(ptr ptr)
 @ stdcall CancelWaitableTimer(long)

include/winbase.h

@@ -1694,6 +1694,7 @@ WINBASEAPI BOOL        WINAPI CallNamedPipeW(LPCWSTR,LPVOID,DWORD,LPVOID,DWORD,L
 #define                       CallNamedPipe WINELIB_NAME_AW(CallNamedPipe)
 WINBASEAPI BOOL        WINAPI CancelIo(HANDLE);
 WINBASEAPI BOOL        WINAPI CancelIoEx(HANDLE,LPOVERLAPPED);
+WINBASEAPI BOOL        WINAPI CancelSynchronousIo(HANDLE);
 WINBASEAPI BOOL        WINAPI CancelTimerQueueTimer(HANDLE,HANDLE);
 WINBASEAPI BOOL        WINAPI CancelWaitableTimer(HANDLE);
 WINBASEAPI BOOL        WINAPI CheckNameLegalDOS8Dot3A(const char*,char*,DWORD,BOOL*,BOOL*);