replace flet with cl-letf.
replace flet with cl-letf.

flet is obsolete as of 24.3. i've opted to use cl-letf to allow us to
achieve the same effect we were granted through our use of flet as
detailed in the blog post entitled:

"Understanding letf and how it replaces flet"
http://endlessparentheses.com/understanding-letf-and-how-it-replaces-flet.html

ennocramer/floskell,sighingnow/hindent,cblp/hindent