[CM] Lint suggests do

[bil at ccrma.Stanford.EDU]

It's mostly stylistic -- I hate named let.  But
I think a do-loop is nearly always faster in s7
due to its roots in Snd.  I can add a flag to control
that report if you like.  Please let me know of any
stupidities in lint -- I use it a lot, but
I am set in my ways.