From inspecting the call sites of utoa, it appears that some of them
(especially the recent cleanup patch which added the strdup there) wanted
to prevent overwriting a local variable by repeated call (to utoa) using
the same variable as argument. This commit instead makes such call sites
strdup the variable itself before passing it to utoa. That seems cleaner
considering that it does not seem utoa's contract to do so (strdup its
parameter that is).
775a97dbd9