FcDirCacheWrite crashes

[hughbe]

	if (access ((char *) test_dir, W_OK|X_OK) == 0)
	{
	    cache_dir = test_dir;
	    break;
	}

W_OK|X_OK=3

but this is invalid on WIndows: https://msdn.microsoft.com/en-us/library/1w06ktdy.aspx?f=255&MSPPError=-2147217396