Hmm, you're right:

```
$ ./easybuild/scripts/eb_sandbox.sh -c 881
Using /var/folders/8s/_frgh9sj6m744mxt5w5lyztr0000gn/T//eb_sandbox_20140522_15-01-05_8cw4H as sandbox
Fetching EasyBuild repositories into /var/folders/8s/_frgh9sj6m744mxt5w5lyztr0000gn/T//eb_sandbox_20140522_15-01-05_8cw4H
./easybuild/scripts/eb_sandbox.sh: line 108: curl: command not found
./easybuild/scripts/eb_sandbox.sh: line 108: curl: command not found
Running 'eb --buildpath /var/folders/8s/_frgh9sj6m744mxt5w5lyztr0000gn/T//eb_sandbox_20140522_15-01-05_8cw4H --installpath /var/folders/8s/_frgh9sj6m744mxt5w5lyztr0000gn/T//eb_sandbox_20140522_15-01-05_8cw4H --force --debug   --from-pr=881' in /Users/kehoste/work/easybuild-framework
```

I'll add a check based on `which curl` exit code.