The `=> :build` seems to be necessary to make @BrewTestBot happy. Without this I'm getting

> Error: 4 problems in 1 formulae
> osxfuse:
> * stable version 2.6.1 is redundant with version scanned from URL
> * autoconf dependency should be "depends_on 'autoconf' => :build"
> * automake dependency should be "depends_on 'automake' => :build"
> * Don't need to interpolate "prefix" with system