Trying to embed font files: does nothing

[ukch]

I'm trying to use this script to programmatically convert the font files from the 'fontawesome' library, and it seems to be doing nothing. Here's the relevant section of my Gruntfile:

....
    imageEmbed: {
        dist: {
            src: ["bower_components/font-awesome/css/font-awesome.css"],
            dest: "<%= dist_dir %>/css/external2.css"
        }
    },
....

And here's the relevant part font-awesome.css:

@font-face {
  font-family: 'FontAwesome';
  src: url('../fonts/fontawesome-webfont.eot?v=4.2.0');
  src: url('../fonts/fontawesome-webfont.eot?#iefix&v=4.2.0') format('embedded-opentype'), url('../fonts/fontawesome-webfont.woff?v=4.2.0') format('woff'), url('../fonts/fontawesome-webfont.ttf?v=4.2.0') format('truetype'), url('../fonts/fontawesome-webfont.svg?v=4.2.0#fontawesomeregular') format('svg');
  font-weight: normal;
  font-style: normal;
}

Running my grunt command gives me some positive-looking output:

Running "imageEmbed:dist" (imageEmbed) task
Encoding file: bower_components/font-awesome/fonts/fontawesome-webfont.eot
Encoding file: bower_components/font-awesome/fonts/fontawesome-webfont.eot
Encoding file: bower_components/font-awesome/fonts/fontawesome-webfont.woff
Encoding file: bower_components/font-awesome/fonts/fontawesome-webfont.ttf
Encoding file: bower_components/font-awesome/fonts/fontawesome-webfont.svg
File "../dist/css/external2.css" created.

Done, without errors.

But when doing a diff on the new file, it is exactly the same as the original.