[fetchmail][PATCH] general cleanup and anti-format-string patch

I was feeling bored, and way too pissed at gdb to try to debug #101792 and
#101950, so I've done a general cleanup in fetchmail.

The patch fixes nearly all gcc -Wall warnings (most of them justified :P),
and changes lots of sprintfs to snprintf. Same for strcat -> strncat.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh

cleanup.patch
Description: Text document