keep spinning even without new line

[Ricardo Wurmus]

Hi Guix,

when using “guix package -i” the build log lines are replaced with a
spinner character.  In some cases, the build log does not produce new
lines for a long time, so that the spinner appears to be stuck.

What do you think of advancing the spinner even when the build log is
not verbose enough to trigger the display of the next character?  How
can this be accomplished?

-- 
Ricardo