.scss {
	@include background(linear-gradient(#ffffff, #F6F6F6));
}
// becomes
.css {
	background: -webkit-linear-gradient(#ffffff, #f6f6f6);
	background: -moz-linear-gradient(#ffffff, #f6f6f6);
	background: -o-linear-gradient(#ffffff, #f6f6f6);
	background: linear-gradient(#ffffff, #f6f6f6);
}

No longer using Compass. Going with Prepros (on Mac) with Autoprefixer enabled (so no @include needed, just straight CSS).