make sure there is exactly one prototype for each function,
use K&R style definitions everywhere to match dominant style,
make flag_signal take an int to avoid problems if we have
ANSI prototypes and K&R definitions.
1. Cleanups of ident_stream. "Evil" stdio is less used.
2. The BSD Copyright was added to the top of builtins.c.
3. As suggested, a timeout is now implemented in the ident
service. It defaults to 10 seconds. If enough people want
it, I'll make it configurable.
Suggested by: msmith
