Windows: workaround freezing of waiting dialog but setting its parent to the desktop and making all mount calls in a separate thread. DeviceIoControl is making our like hard because it doesn't behave as a normal system call and it blocks our window message loop even when called from a separate thread.

src/Common/Dlgcode.c

@@ -6369,9 +6369,9 @@ retry:
 		threadParam.pmount = &mount;
 		threadParam.pbResult = &bResult;
 		threadParam.pdwResult = &dwResult;
-
+		
 		DialogBoxParamW (hInst,
-					MAKEINTRESOURCEW (IDD_STATIC_MODAL_WAIT_DLG), hwndDlg,
+					MAKEINTRESOURCEW (IDD_STATIC_MODAL_WAIT_DLG), GetDesktopWindow(),
 					(DLGPROC) MountWaitDlgProc, (LPARAM) &threadParam);
 	}
 	else