Apparently the handling of `buildFlagsArray` in `buildGo*` is blatantly
broken since it doesn't quote flags specified as list elements properly.
Because of that, the `-ldflags` are not interpreted properly and
`prometheus --version` doesn't output anything useful. By specifying
flags in both `buildFlags` and `buildFlagsArray` the issue gets fixed
since both variables are passed to `go install`.
