Got rid of the rest of the warnings that I didn't have time for on 1999-07-15

Got rid of the rest of the warnings that I didn't have time for on 1999-07-15
(and, it would seem, some new ones people introduced since then).  The primary
ones were the warnings that default prototypes were being used for [v]snprintf()
and str[n]casecmp().  As of right now, there are _no_ compilation warnings
except on the lex output file (at least under AIX 4.1.5 and Solaris 2.6).