Otherwise the output is going to be something like this when the plugin
cannot be built, which is ugly:
```
write_sensu . . . . . yes
write_stackdriver . .
write_tsdb . . . . . yes
```
plugin_vserver="no"
plugin_wireless="no"
plugin_write_prometheus="no"
plugin_vserver="no"
plugin_wireless="no"
plugin_write_prometheus="no"
+plugin_write_stackdriver="no"
plugin_xencpu="no"
plugin_zfs_arc="no"
plugin_zone="no"
plugin_xencpu="no"
plugin_zfs_arc="no"
plugin_zone="no"