XHTML incompatible

tried to run it with `htmlmin -p img link --keep-optional-attribute-quotes file.xhtml file_minified.xhtml`
but I get error because still `<link href="style.css" type="text/css" rel="stylesheet" />` gets converted to `<link href="style.css" type="text/css" rel="stylesheet">` and `<img src="image.gif" alt="" />` to `<img src="image.gif" alt>`