[tlbuild] Build -g

[Karl Berry]

    This turns out to be a bash issue, reflecting the fact that time is 
    *both* a bash builtin and an external command (even in linux); see

I figured it was something about that, but didn't imagine that you
didn't have an external time installed!  It's a fundamental command,
after all.  Shouldn't rely on shells to provide it.

I'm not sure offhand how to rearrange the invocation to make it robust
against the lack of an external time, but I guess it's a moot point now?

Thanks,
k