opened
shurcooL
username_0
So this line, for example, would fail to work as expected if one has 2 or more workspaces:

```Go
fi, err := ioutil.ReadDir(build.Default.GOPATH + "/bin")
```

Because the value of `build.Default.GOPATH` would be something like `/path/to/workspace1:/path/to/workspace2`.

The correct solution is to use [`filepath.SplitList`](https://godoc.org/path/filepath#SplitList) to parse GOPATH environment variable and extract all workspaces that are included. Then, you'd want to process them in a way that works.

You can look at `binstale` for [an example](https://github.com/username_0/binstale/blob/14c3c3e47f8a05aa0396e611d616d9487cfe040d/main.go#L59) of how to work with multiple workspaces.
gorebuild will fail in environments where GOPATH includes 2 or more workspaces.
issue